Sea to Summit Ether Light XT Extreme Sleeping Mat (Large)
The Ether Light XT Extreme is extra thick and exceptionally warm. The XT Air Sprung Cells provide 10 cm of stability and comfort, while dual-density layers of THERMOLITE insulation prevent convective heat loss and internal air movement. This results in true four-season performance. Features 6.2 R-Value is perfect for cold weather adventures. At 10 cm thick, Ether Light XT Air Sprung Cells provides a plush sleeping experience. Dual-density layers of Thermolite insulation fill the inner space, preventing heat loss due to convection and internal air movement. Lighter, quieter and durable 30D/40D face fabric with Sea to Summits liquid-extruded lamination is extremely reliable. Quick and easy inflation, deflation and adjustment is made possible by our multi-function valve and supplied Airstream Pump/stuff sack. Anti-microbial treatment added to the TPU lamination formula prevents internal mold growth. PillowLock system prevents your Sea to Summit Aeros Pillow from slipping. Comes with a stuff sack which doubles as a pump, a repair kit with six self-adhesive patches and a spare valve insert.
The Ether Light XT Extreme is extra thick and exceptionally warm. The XT Air Sprung Cells provide 10 cm of stability and comfort, while dual-density layers of THERMOLITE insulation prevent convective heat loss and internal air movement. This results in true four-season performance. Features 6.2 R-Value is perfect for cold weather adventures. At 10 cm thick, Ether Light XT Air Sprung Cells provides a plush sleeping experience. Dual-density layers of Thermolite insulation fill the inner space, preventing heat loss due to convection and internal air movement. Lighter, quieter and durable 30D/40D face fabric with Sea to Summits liquid-extruded lamination is extremely reliable. Quick and easy inflation, deflation and adjustment is made possible by our multi-function valve and supplied Airstream Pump/stuff sack. Anti-microbial treatment added to the TPU lamination formula prevents internal mold growth. PillowLock system prevents your Sea to Summit Aeros Pillow from slipping. Comes with a stuff sack which doubles as a pump, a repair kit with six self-adhesive patches and a spare valve insert.
The Ether Light XT Extreme is extra thick and exceptionally warm. The XT Air Sprung Cells provide 10 cm of stability and comfort, while dual-density layers of THERMOLITE insulation prevent convective heat loss and internal air movement. This results in true four-season performance. Features 6.2 R-Value is perfect for cold weather adventures. At 10 cm thick, Ether Light XT Air Sprung Cells provides a plush sleeping experience. Dual-density layers of Thermolite insulation fill the inner space, preventing heat loss due to convection and internal air movement. Lighter, quieter and durable 30D/40D face fabric with Sea to Summits liquid-extruded lamination is extremely reliable. Quick and easy inflation, deflation and adjustment is made possible by our multi-function valve and supplied Airstream Pump/stuff sack. Anti-microbial treatment added to the TPU lamination formula prevents internal mold growth. PillowLock system prevents your Sea to Summit Aeros Pillow from slipping. Comes with a stuff sack which doubles as a pump, a repair kit with six self-adhesive patches and a spare valve insert.
The Ether Light XT Extreme is extra thick and exceptionally warm. The XT Air Sprung Cells provide 10 cm of stability and comfort, while dual-density layers of THERMOLITE insulation prevent convective heat loss and internal air movement. This results in true four-season performance. Features 6.2 R-Value is perfect for cold weather adventures. At 10 cm thick, Ether Light XT Air Sprung Cells provides a plush sleeping experience. Dual-density layers of Thermolite insulation fill the inner space, preventing heat loss due to convection and internal air movement. Lighter, quieter and durable 30D/40D face fabric with Sea to Summits liquid-extruded lamination is extremely reliable. Quick and easy inflation, deflation and adjustment is made possible by our multi-function valve and supplied Airstream Pump/stuff sack. Anti-microbial treatment added to the TPU lamination formula prevents internal mold growth. PillowLock system prevents your Sea to Summit Aeros Pillow from slipping. Comes with a stuff sack which doubles as a pump, a repair kit with six self-adhesive patches and a spare valve insert.
in 4 offers
The lowest price for Sea to Summit Ether Light XT Extreme Sleeping Mat (Large) right now is $311.00 at Sticky Bottle, compared across 4 retailers.
The all-time low was $274.99 on 6 Mar 2026 — today's price is 13% above the lowest ever. That's a little above the best price we've seen.
Prices last updated 5 June 2026.
Last updated at 05/06/2026 20:07:07
Sea To Summit - Ether LightXT Extreme Sleeping mat -
Free delivery between 11–19 June
Sea to Summit Ether Light XT Extreme Sleeping Mat (Large)
Free delivery between 11–15 June
Sea To Summit Ether Light Xt Extreme Inflatable Mat Black 198 x 64 cm
Delivery $42.99
Ether Light XT Extreme ASC Mat Large
Free delivery
originally posted on altitude-sports.com
Amazing product - the pillow keeper is such a wonderful plus if you've already purchased a S2S compatible product. Super warm with a great R-value. Worked wonderfully over 12-days in Newfoundland at sub-zero temps. Im a side sleeper and the extra thickness is wonderful. Great length for people over 6'. Zero complaints, wonderful design - not too noisey either which is a huge plus. Will update the review after winter comes along to really put it through the ringer
originally posted on seatosummit.com
This product meet and exceeded my expectations! After my first one was destroyed in a storm on a motorcycle trip to the badlands back in August. I knew I needed to replace before my backpacking trip near Aspen Co. After waiting too long to order a new one I decided to take my product right to your wear house in Boulder. Left the next morning and slept in a foot of snow above 11,oooft and could have not gotten a better nights sleep after a nine miles out. This product had no problem keeping air throughout the night and not once felt the cold ground underneath me. Ill be honest and did not have all the right gear for the conditions but I am would not have made it through the night without the model Ether Light XT Extreme Air Sleeping Pad!! Packing and unpacking was no ... MoreThis product meet and exceeded my expectations! After my first one was destroyed in a storm on a motorcycle trip to the badlands back in August. I knew I needed to replace before my backpacking trip near Aspen Co. After waiting too long to order a new one I decided to take my product right to your wear house in Boulder. Left the next morning and slept in a foot of snow above 11,oooft and could have not gotten a better nights sleep after a nine miles out. This product had no problem keeping air throughout the night and not once felt the cold ground underneath me. Ill be honest and did not have all the right gear for the conditions but I am would not have made it through the night without the model Ether Light XT Extreme Air Sleeping Pad!! Packing and unpacking was no issues even in below zero degree temps. I did not get a chance to use the pillow lock system but wish I had set it up because that was the only issue was my pillow moving. Totally my fault not the product and I look forward to installing the pillow lock system before the next use!!
originally posted on seatosummitusa.com
I knew the instant I opened the brand-new package that it would be a nightmare to pack up after using it. It is a common problem I've encountered over the years with tents and sleeping bags and such by many manufacturers. You get them and even coming from the factory after being vacuum compressed the thing barely fits in its carry bag. Rolling it back up to factory level tightness is extremely difficult in the field yet so many companies, including Sea to Summit, it seems, can't be bothered to provide even a little bit of extra room in the stuff sack to give you some margin for error.I had to re-roll it three times in my living room being extremely careful to maximize perfection when I first got it. This is an absolute NIGHTMARE in the field. Especially for a pad ... MoreI knew the instant I opened the brand-new package that it would be a nightmare to pack up after using it. It is a common problem I've encountered over the years with tents and sleeping bags and such by many manufacturers. You get them and even coming from the factory after being vacuum compressed the thing barely fits in its carry bag. Rolling it back up to factory level tightness is extremely difficult in the field yet so many companies, including Sea to Summit, it seems, can't be bothered to provide even a little bit of extra room in the stuff sack to give you some margin for error.I had to re-roll it three times in my living room being extremely careful to maximize perfection when I first got it. This is an absolute NIGHTMARE in the field. Especially for a pad like this that is designed for extreme cold. The last thing I want to have to deal with is trying to perfectly roll a pad at -30 degrees with my bare hands... I will likely have to find another carrying bag for it for true cold camping this winter. (which will be annoying because the carry bag is also the inflation bag)This is something I love about my therm-o-rest. It has extra space, and packing it up is trivial and easy because the bag is 10% bigger than it needs to be.That said, other than the infuriatingly small carry case this is a fantastic sleeping pad. Easily the best I've ever used. Far more comfortable than any Therm-o-rest that I've used. This is the closest pad I've ever had to feeling like a real bed. I haven't tested it in extreme conditions yet to see how true the R of 6.3 is but so far VERY HAPPY with the pad itself.5 stars for the pad, 1 star for the carry bag. Averages out to 3. ;)
| R-rating | 6.0 + |
| Sea to Summit Ether Light XT Extreme | R |
| R-value | 6.2 |
| Thickness (cm) | 10.0 |
| Length (cm) | 183 |
Sea To Summit - Ether LightXT Extreme Sleeping mat -
Free delivery between 11–19 June
Sea to Summit Ether Light XT Extreme Sleeping Mat (Large)
Free delivery between 11–15 June
Sea To Summit Ether Light Xt Extreme Inflatable Mat Black 198 x 64 cm
Delivery $42.99
Ether Light XT Extreme ASC Mat Large
Free delivery
Amazing product - the pillow keeper is such a wonderful plus if you've already purchased a S2S compatible product. Super warm with a great R-value. Worked wonderfully over 12-days in Newfoundland at sub-zero temps. Im a side sleeper and the extra thickness is wonderful. Great length for people over 6'. Zero complaints, wonderful design - not too noisey either which is a huge plus. Will update the review after winter comes along to really put it through the ringer
This product meet and exceeded my expectations! After my first one was destroyed in a storm on a motorcycle trip to the badlands back in August. I knew I needed to replace before my backpacking trip near Aspen Co. After waiting too long to order a new one I decided to take my product right to your wear house in Boulder. Left the next morning and slept in a foot of snow above 11,oooft and could have not gotten a better nights sleep after a nine miles out. This product had no problem keeping air throughout the night and not once felt the cold ground underneath me. Ill be honest and did not have all the right gear for the conditions but I am would not have made it through the night without the model Ether Light XT Extreme Air Sleeping Pad!! Packing and unpacking was no ... MoreThis product meet and exceeded my expectations! After my first one was destroyed in a storm on a motorcycle trip to the badlands back in August. I knew I needed to replace before my backpacking trip near Aspen Co. After waiting too long to order a new one I decided to take my product right to your wear house in Boulder. Left the next morning and slept in a foot of snow above 11,oooft and could have not gotten a better nights sleep after a nine miles out. This product had no problem keeping air throughout the night and not once felt the cold ground underneath me. Ill be honest and did not have all the right gear for the conditions but I am would not have made it through the night without the model Ether Light XT Extreme Air Sleeping Pad!! Packing and unpacking was no issues even in below zero degree temps. I did not get a chance to use the pillow lock system but wish I had set it up because that was the only issue was my pillow moving. Totally my fault not the product and I look forward to installing the pillow lock system before the next use!!
I knew the instant I opened the brand-new package that it would be a nightmare to pack up after using it. It is a common problem I've encountered over the years with tents and sleeping bags and such by many manufacturers. You get them and even coming from the factory after being vacuum compressed the thing barely fits in its carry bag. Rolling it back up to factory level tightness is extremely difficult in the field yet so many companies, including Sea to Summit, it seems, can't be bothered to provide even a little bit of extra room in the stuff sack to give you some margin for error.I had to re-roll it three times in my living room being extremely careful to maximize perfection when I first got it. This is an absolute NIGHTMARE in the field. Especially for a pad ... MoreI knew the instant I opened the brand-new package that it would be a nightmare to pack up after using it. It is a common problem I've encountered over the years with tents and sleeping bags and such by many manufacturers. You get them and even coming from the factory after being vacuum compressed the thing barely fits in its carry bag. Rolling it back up to factory level tightness is extremely difficult in the field yet so many companies, including Sea to Summit, it seems, can't be bothered to provide even a little bit of extra room in the stuff sack to give you some margin for error.I had to re-roll it three times in my living room being extremely careful to maximize perfection when I first got it. This is an absolute NIGHTMARE in the field. Especially for a pad like this that is designed for extreme cold. The last thing I want to have to deal with is trying to perfectly roll a pad at -30 degrees with my bare hands... I will likely have to find another carrying bag for it for true cold camping this winter. (which will be annoying because the carry bag is also the inflation bag)This is something I love about my therm-o-rest. It has extra space, and packing it up is trivial and easy because the bag is 10% bigger than it needs to be.That said, other than the infuriatingly small carry case this is a fantastic sleeping pad. Easily the best I've ever used. Far more comfortable than any Therm-o-rest that I've used. This is the closest pad I've ever had to feeling like a real bed. I haven't tested it in extreme conditions yet to see how true the R of 6.3 is but so far VERY HAPPY with the pad itself.5 stars for the pad, 1 star for the carry bag. Averages out to 3. ;)
I was hesitant to buy, then I had buyers remorse because I did not appreciate its design and best use. Being a car camper who regularly uses an exped 10cm sim, this mat required some getting used to. Since my remorse, I’ve taken it through its paces on 1 or 5 night trips. I’ve used it on the ground and once as a mattress on top of a camp bunk. If you have a crunchy nylon type sleeping bag and this mat, you’ll find it challenging to stay on the mat and likely hear yourself twist and turn in your sleep. I bought a S2S sleeping liner (the stretchy fabric one) and I place the mat inside this. This has helped immensely with the noise, and it keeps the mat cleaner. I use a 65l hiking backpack and it fits in the pack, but as others have said - the mat is bulky when rolled ... MoreI was hesitant to buy, then I had buyers remorse because I did not appreciate its design and best use. Being a car camper who regularly uses an exped 10cm sim, this mat required some getting used to. Since my remorse, I’ve taken it through its paces on 1 or 5 night trips. I’ve used it on the ground and once as a mattress on top of a camp bunk. If you have a crunchy nylon type sleeping bag and this mat, you’ll find it challenging to stay on the mat and likely hear yourself twist and turn in your sleep. I bought a S2S sleeping liner (the stretchy fabric one) and I place the mat inside this. This has helped immensely with the noise, and it keeps the mat cleaner. I use a 65l hiking backpack and it fits in the pack, but as others have said - the mat is bulky when rolled up and will take considerable space in your backpack. That being said, I fit my clothes, mont 3p tent, and an nevegear quilt, but I would have struggled to fit food in. That isn’t because of my mat choice, just cos I overpacked clothes. This mat will work for anyone if they give it time. I bought another mat - for my child as the mat works for packing for Scout camps as it fits into a 32l hiking backpack. I choose this because the R value is great, we are cold sleepers, and on top of an Exped flex mat - we get above 7 R value. I know my scout is warm. We camp with temperatures below 5 degrees. Can I say I just love how fast it deflates. I was packed and ready to leave in record time at a recent scout camp. We also have the S2S Comfort Plus Self Inflating Rectangular Sleeping Mat, and between the two, I prefer the Ether Light XT Extreme Insulated and I pack it as first preference for cold camping (anything after Feb in Victoria, Au) and it’s lighter (950g) compared to the comfort plus (1.3kg)
I love this mat, I use it even as an air mattress when visiting family and friends. It's very comfortable and when inflated properly it's very warm. I don't find the noise I hear other reviews comment about as a problem (it seems average for an inflatable to me). That all said, I take one star away solely due to the large packed size. For backpacking or mountaineering this takes up nearly as much space as my down sleeping bag.I am happy with it overall as I prefer comfort when sleeping to carried space and weight.
I have a R4.2 ultralight for bikepacking but needed a thicker alpine rated mat for Tasmania. Firstly I'm comparing with an ultralight and not a similar like for like. Bulk - I'm using this for hiking so bulk isn't as important than for bikepacking for me. I also don't stuff the mat but fold it to use as the padding of my frameless pack. I didn't find this bulky at all when used this way. Weight was not an issue either. Ease of set up - This was brilliant and quick using the blow up sack. I feel good knowing I'm blowing less moisture into the mat. Deflating and pushing out the air was very quick and easy. Comfort - Very thick but best not to inflate it completely, a bit less is more comfortable. Able to sleep on side well. Noise - Only downside, it has a slight ... MoreI have a R4.2 ultralight for bikepacking but needed a thicker alpine rated mat for Tasmania. Firstly I'm comparing with an ultralight and not a similar like for like. Bulk - I'm using this for hiking so bulk isn't as important than for bikepacking for me. I also don't stuff the mat but fold it to use as the padding of my frameless pack. I didn't find this bulky at all when used this way. Weight was not an issue either. Ease of set up - This was brilliant and quick using the blow up sack. I feel good knowing I'm blowing less moisture into the mat. Deflating and pushing out the air was very quick and easy. Comfort - Very thick but best not to inflate it completely, a bit less is more comfortable. Able to sleep on side well. Noise - Only downside, it has a slight crinkling noise but not too bad. My fellow campers said they could hear 'someone' move but that it wasn't annoying.
I got this mat for an expedition this past summer in the Peruvian Andes, slept with it up to 16000 feet in as cold as 5 degrees and I can confidently say that my back was never cold and I slept very well on it. I will say that I wish I had gotten the rectangular pad as I felt it was slightly narrow especially when fully inflated, I am not a huge person 5'8" and 160lbs but have relatively wide shoulders. While no part of me was hanging over the edges the mat does not allow much movement room side to side. It is somewhat slippery so sleeping on any incline did see me slide somewhat over the course of the night especially if I moved around. The only other complaint I have is with the pillow lock velcro, I found that when it would get really cold and after inflating and ... MoreI got this mat for an expedition this past summer in the Peruvian Andes, slept with it up to 16000 feet in as cold as 5 degrees and I can confidently say that my back was never cold and I slept very well on it. I will say that I wish I had gotten the rectangular pad as I felt it was slightly narrow especially when fully inflated, I am not a huge person 5'8" and 160lbs but have relatively wide shoulders. While no part of me was hanging over the edges the mat does not allow much movement room side to side. It is somewhat slippery so sleeping on any incline did see me slide somewhat over the course of the night especially if I moved around. The only other complaint I have is with the pillow lock velcro, I found that when it would get really cold and after inflating and deflating multiple times that one of the four velcro stickers that came with the pad basically just popped off and wouldn't re-adhere, didn't really hinder the locking performance of the pillow much but a little annoying, wish there were extras when you pay 200+ for a sleeping pad. The integrated inflation sac was amazing, 3-4 pumps and it was completely inflated, easily within 1 minute.
To give context to my review, first some personal notes. 1. I am a side sleeper who likes to rotate a fair bit in my sleep. 2. I have suffered back injury and trauma meaning I cannot lie flat on my back and experience regular back pain. 3. Nerve damage from my back means I now feel the cold significantly in my upper thighs (even when the rest of me is over heating) 4. Female - 40yrs and not a light weight anymore :(After many decades of hiking and surviving ( comfortably) with a close cell foam mat and average sleeping bag, back trauma found me struggling to get any quality of sleep. After doing significant research into mats and coming down to this or the Thermorest NeoAir Xtherm. Weighing up all the pros and cons for my situation. I decided, as a side sleeper, ... MoreTo give context to my review, first some personal notes. 1. I am a side sleeper who likes to rotate a fair bit in my sleep. 2. I have suffered back injury and trauma meaning I cannot lie flat on my back and experience regular back pain. 3. Nerve damage from my back means I now feel the cold significantly in my upper thighs (even when the rest of me is over heating) 4. Female - 40yrs and not a light weight anymore :(After many decades of hiking and surviving ( comfortably) with a close cell foam mat and average sleeping bag, back trauma found me struggling to get any quality of sleep. After doing significant research into mats and coming down to this or the Thermorest NeoAir Xtherm. Weighing up all the pros and cons for my situation. I decided, as a side sleeper, and with comfort for my back being priority, that this was the best option (also for the bank account). I also decided to stick with the regular tapered rectangle. (for weight and cost reasons) I also splashed out and paired this mat with the Sea to Summit Accent III sleeping bag to give added warmth (also not the lightest or smallest but good price for the great value you get!) My first test was at home, to get the air comfort level right, and I am glad I did. This mat is far more comfy when not filled tight with air as this allows the mat to support and cushion around you as needed. Since then I have used this mat on three trips with over night temps from 4 degrees to - 3 degrees. On all trips I slept warm and comfortably (I still just use my pack with clothing layers etc inside for my pillow) to the point where I noted I hardly moved during the nights and could stay comfortably on one side the majority of the night. I initially thought I should have gone for the rectangular regular rather than the tapered because I am a restless sleeper, but to be honest, I did not have a problem even though I use the full length and width of the mat. I did not find the mat noisy at all. When initially getting into bed, I felt the usual cold I do in my upper thighs, but after doing a few 'in-bag-exercises" to build heat, found that I did not feel the cold and certainly was not woken by it throughout the nights. In the mornings I didn't struggle with back pain like I previously have. Generally I felt amazing, the best hiking sleeps I have had in years. Overall I was beyond pleasantly surprised with the performance of this mat and bag for my situation.Advice 1. Be confident in why you want this mat and what personal needs it is meeting. (side sleeping, warmth etc) 2. Know what you are willing to sacrifice and the reason you are doing so. ie) weight for comfort / size for cost and weight. 3. Before taking it 'out' for the first time, test it out at home to get your comfort air level right - this makes the world of difference. 4. Know that you are getting value for money. Happy Hiking!
I have used this pad in temps down to 15F and was very warm. I suffer from lower back pain, this pad is hit or miss with me. Sometimes I sleep great with no problems and other times I wake up with my lower back in a lot of pain. I decided to go with a self inflating pad with foam because its better for my lower back, the comfort plus. If you don't suffer from back problems, this pad is great. It very lightweight, little on the bulky side. I have been using it for over a year and overall its a good pad, just not if you have back pain.
I found this pad to be the most comfortable laying on them in store. Large rolled up, you can see the insulation inside by the thickness of the pad. I would love something a bit smaller. The Xtherm is too flat and uncomfortable for me to want to buy and risk not being able to return. As well as being loud. (Potato chip bag) It being the lightest and smallest (until the tensor Extreme?)This pad is quiet, I don’t know how anyone could expect it to be quieter. Comfortable. I do wish it were a higher rating and lighter. I’m afraid of trying the tensor extreme.Got the regular size - you’ll not be wanting to move around too much on it. Feet will fall off. If that’s a problem for you you’ll want to grab a larger. Get it on sale these things are expensive!Also, ... MoreI found this pad to be the most comfortable laying on them in store. Large rolled up, you can see the insulation inside by the thickness of the pad. I would love something a bit smaller. The Xtherm is too flat and uncomfortable for me to want to buy and risk not being able to return. As well as being loud. (Potato chip bag) It being the lightest and smallest (until the tensor Extreme?)This pad is quiet, I don’t know how anyone could expect it to be quieter. Comfortable. I do wish it were a higher rating and lighter. I’m afraid of trying the tensor extreme.Got the regular size - you’ll not be wanting to move around too much on it. Feet will fall off. If that’s a problem for you you’ll want to grab a larger. Get it on sale these things are expensive!Also, stuffsack is easy. Inflating is a piece of cake. Quick too!
| R-rating | 6.0 + |
| Sea to Summit Ether Light XT Extreme | R |
| R-value | 6.2 |
| Thickness (cm) | 10.0 |
| Length (cm) | 183 |
