Sea to Summit Ether Light XT Extreme Sleeping Mat (Rectangular Wide)
With an R-value over 6, the 10cm thick EtherLightXT Extreme air mat redefines lightweight sleeping comfort for winter adventures around the globe. Sea to Summit's Air Sprung Cells are the reason you will sleep better on this air mat. Each Air Sprung Cell deforms independently and allows the mat to conform to your body shape. This provides support and comfort by more evenly dispersing pressure across the mat's surface. For the extra thick (XT) EtherLight design, many TPU loops are used to connect the top and bottom fabric layers to the Air Sprung Cell dot weld pattern. These loops allow the top and bottom layers to be positioned further apart which creates larger pockets of air when inflated-perfect for side sleepers. This design also requires less fabric overall which means great stability and comfort for less weight. Dual-density layers of THERMOLITE insulation fill the Air Sprung Cells and work together to prevent convective heat transfer and boost warmth while remaining lightweight and packable. When the mercury drops, the EtherLightXT Extreme's 6.2 (women's 6.3) ASTM R-value will keep you cushioned and insulated from the cold hard lumps and bumps beneath.
With an R-value over 6, the 10cm thick EtherLightXT Extreme air mat redefines lightweight sleeping comfort for winter adventures around the globe. Sea to Summit's Air Sprung Cells are the reason you will sleep better on this air mat. Each Air Sprung Cell deforms independently and allows the mat to conform to your body shape. This provides support and comfort by more evenly dispersing pressure across the mat's surface. For the extra thick (XT) EtherLight design, many TPU loops are used to connect the top and bottom fabric layers to the Air Sprung Cell dot weld pattern. These loops allow the top and bottom layers to be positioned further apart which creates larger pockets of air when inflated-perfect for side sleepers. This design also requires less fabric overall which means great stability and comfort for less weight. Dual-density layers of THERMOLITE insulation fill the Air Sprung Cells and work together to prevent convective heat transfer and boost warmth while remaining lightweight and packable. When the mercury drops, the EtherLightXT Extreme's 6.2 (women's 6.3) ASTM R-value will keep you cushioned and insulated from the cold hard lumps and bumps beneath.
With an R-value over 6, the 10cm thick EtherLightXT Extreme air mat redefines lightweight sleeping comfort for winter adventures around the globe. Sea to Summit's Air Sprung Cells are the reason you will sleep better on this air mat. Each Air Sprung Cell deforms independently and allows the mat to conform to your body shape. This provides support and comfort by more evenly dispersing pressure across the mat's surface. For the extra thick (XT) EtherLight design, many TPU loops are used to connect the top and bottom fabric layers to the Air Sprung Cell dot weld pattern. These loops allow the top and bottom layers to be positioned further apart which creates larger pockets of air when inflated-perfect for side sleepers. This design also requires less fabric overall which means great stability and comfort for less weight. Dual-density layers of THERMOLITE insulation fill the Air Sprung Cells and work together to prevent convective heat transfer and boost warmth while remaining lightweight and packable. When the mercury drops, the EtherLightXT Extreme's 6.2 (women's 6.3) ASTM R-value will keep you cushioned and insulated from the cold hard lumps and bumps beneath.
With an R-value over 6, the 10cm thick EtherLightXT Extreme air mat redefines lightweight sleeping comfort for winter adventures around the globe. Sea to Summit's Air Sprung Cells are the reason you will sleep better on this air mat. Each Air Sprung Cell deforms independently and allows the mat to conform to your body shape. This provides support and comfort by more evenly dispersing pressure across the mat's surface. For the extra thick (XT) EtherLight design, many TPU loops are used to connect the top and bottom fabric layers to the Air Sprung Cell dot weld pattern. These loops allow the top and bottom layers to be positioned further apart which creates larger pockets of air when inflated-perfect for side sleepers. This design also requires less fabric overall which means great stability and comfort for less weight. Dual-density layers of THERMOLITE insulation fill the Air Sprung Cells and work together to prevent convective heat transfer and boost warmth while remaining lightweight and packable. When the mercury drops, the EtherLightXT Extreme's 6.2 (women's 6.3) ASTM R-value will keep you cushioned and insulated from the cold hard lumps and bumps beneath.
in 4 offers
The lowest price for Sea to Summit Ether Light XT Extreme Sleeping Mat (Rectangular Wide) right now is $314.99 at K2 Base Camp, compared across 4 retailers.
The all-time low was $301.73 on 15 Sept 2025 — today's price is 4% above the lowest ever. This is at or near its all-time low — a good time to buy.
Prices last updated 15 May 2026.
Last updated at 15/05/2026 07:50:04
Sea to Summit Ether Light XT Extreme Sleeping Mat Rectangular Regular Wide
Free delivery between Tue – Thu
Sea To Summit Ether Light XT Extreme Air Sleeping Mat (with Handpump) Rectangular Regular Wide
Delivery $45.67
Sea To Summit Ether Light XT Extreme Mat Rectangular RW Black-Orange Regular Wide | Pads >10 cm buy
Delivery between 22–28 May $114.49
Sea to Summit Ether Light XT Extreme ASC Mat - Rectangular Regular
Free delivery
originally posted on altitude-sports.com
Finally traded in my old Thermarest and was on the hunt for the most comfort that could be fit in a backpack. At 40 years old, I need a good sleep, and this pad provides that. The additional thickness and extra width makes this great for side sleepers and those who toss in their sleep. Quality seems great. Love the stuff sack that extends into a pump sack. Thoughtful design throughout! Two thumbs up!
originally posted on altitude-sports.com
I have several sleeping pads including the Exped Megamat. This takes second place for comfort and warmth. Even though my Thermarest X-Therm is 6.9 r-value, this feels warmer because of the thickness and the Air Sprung cells. I love the built in airstream pump sack in the storage bag. I bought this pad for my Big Agnes Elk Park -30°C sleeping bag. It fits perfectly. This is a great sleeping pad. Well worth it when it's on sale. Cheers
originally posted on moosejaw.com
A while back I purchased this pad for my partner (5’11”, 200lbs). He’s a princess side sleeper and getting him to go backpacking required a proper sleeping pad. When he wasn’t using it I used it…. So naturally I needed my own (seriously it’s comfy). I have one dog who I always backpack with and have never had an issue with her ruining sleeping pads, my other dog however got to go on his first overnight trip and sliced my brand new pad open….. Thankfully we had 2 repair kits on us and I tried my hardest to patch the thing. But the instructions don’t account for being in the middle of nowhere on the Superior Shoreline so it wasn’t pretty. However I got it to hold some air. I was 100% pouting about this, but after settling into the tent for the night was able to ... MoreA while back I purchased this pad for my partner (5’11”, 200lbs). He’s a princess side sleeper and getting him to go backpacking required a proper sleeping pad. When he wasn’t using it I used it…. So naturally I needed my own (seriously it’s comfy). I have one dog who I always backpack with and have never had an issue with her ruining sleeping pads, my other dog however got to go on his first overnight trip and sliced my brand new pad open….. Thankfully we had 2 repair kits on us and I tried my hardest to patch the thing. But the instructions don’t account for being in the middle of nowhere on the Superior Shoreline so it wasn’t pretty. However I got it to hold some air. I was 100% pouting about this, but after settling into the tent for the night was able to honestly say this pad was amazingly comfortable at 1/3 full….. and I was able to fix the pad for me after getting home (5’4”, 120lbs).
| Sea to Summit Ether Light XT Extreme Rectangular | Regular - Wide |
| R-value | 6.2 |
| Thickness (cm) | 10.0 |
| Length (cm) | 183 |
| Weight (grams) | 950 |
Sea to Summit Ether Light XT Extreme Sleeping Mat Rectangular Regular Wide
Free delivery between Tue – Thu
Sea To Summit Ether Light XT Extreme Air Sleeping Mat (with Handpump) Rectangular Regular Wide
Delivery $45.67
Sea To Summit Ether Light XT Extreme Mat Rectangular RW Black-Orange Regular Wide | Pads >10 cm buy
Delivery between 22–28 May $114.49
Sea to Summit Ether Light XT Extreme ASC Mat - Rectangular Regular
Free delivery
Finally traded in my old Thermarest and was on the hunt for the most comfort that could be fit in a backpack. At 40 years old, I need a good sleep, and this pad provides that. The additional thickness and extra width makes this great for side sleepers and those who toss in their sleep. Quality seems great. Love the stuff sack that extends into a pump sack. Thoughtful design throughout! Two thumbs up!
I have several sleeping pads including the Exped Megamat. This takes second place for comfort and warmth. Even though my Thermarest X-Therm is 6.9 r-value, this feels warmer because of the thickness and the Air Sprung cells. I love the built in airstream pump sack in the storage bag. I bought this pad for my Big Agnes Elk Park -30°C sleeping bag. It fits perfectly. This is a great sleeping pad. Well worth it when it's on sale. Cheers
A while back I purchased this pad for my partner (5’11”, 200lbs). He’s a princess side sleeper and getting him to go backpacking required a proper sleeping pad. When he wasn’t using it I used it…. So naturally I needed my own (seriously it’s comfy). I have one dog who I always backpack with and have never had an issue with her ruining sleeping pads, my other dog however got to go on his first overnight trip and sliced my brand new pad open….. Thankfully we had 2 repair kits on us and I tried my hardest to patch the thing. But the instructions don’t account for being in the middle of nowhere on the Superior Shoreline so it wasn’t pretty. However I got it to hold some air. I was 100% pouting about this, but after settling into the tent for the night was able to ... MoreA while back I purchased this pad for my partner (5’11”, 200lbs). He’s a princess side sleeper and getting him to go backpacking required a proper sleeping pad. When he wasn’t using it I used it…. So naturally I needed my own (seriously it’s comfy). I have one dog who I always backpack with and have never had an issue with her ruining sleeping pads, my other dog however got to go on his first overnight trip and sliced my brand new pad open….. Thankfully we had 2 repair kits on us and I tried my hardest to patch the thing. But the instructions don’t account for being in the middle of nowhere on the Superior Shoreline so it wasn’t pretty. However I got it to hold some air. I was 100% pouting about this, but after settling into the tent for the night was able to honestly say this pad was amazingly comfortable at 1/3 full….. and I was able to fix the pad for me after getting home (5’4”, 120lbs).
This pad is the winter edition of an already very successful Ether Light XT 3-season pad. It retains all the good things going for the Ether Light XT pads, including the quality workmanship, good materials and practical design.There are two big names when it comes to sleeping pads (and a lot a smaller names): Nemo and SeaToSummit. I have both.The pad is quite thick at 4in, heavy and packs larger than my Nemo Tensor. The weight is a trade-off with the insulation and thickness, which makes it a valid proposition for winter camping. A direct competitor would be Nemo Alpine.I like the well designed valve, the rectangular shape, the clever design that allows for the carrying sack to double as a pump. My wife also appreciated the extra thickness of the pad.While the ... MoreThis pad is the winter edition of an already very successful Ether Light XT 3-season pad. It retains all the good things going for the Ether Light XT pads, including the quality workmanship, good materials and practical design.There are two big names when it comes to sleeping pads (and a lot a smaller names): Nemo and SeaToSummit. I have both.The pad is quite thick at 4in, heavy and packs larger than my Nemo Tensor. The weight is a trade-off with the insulation and thickness, which makes it a valid proposition for winter camping. A direct competitor would be Nemo Alpine.I like the well designed valve, the rectangular shape, the clever design that allows for the carrying sack to double as a pump. My wife also appreciated the extra thickness of the pad.While the weight might make it prohibitive for long backpacking trips, this pad will be popular with people who winter camp or campers for who weight is not the primary concern.
Best mattress I have used in my 35 years of bike touring/camping. Yes, it's a bit big and heavy, but some things are worth a bit of extra weight: superior comfort, ease of use, and knowing I won't freeze. It's only about 300 grams more than my neoair xtherm, and much better in every way.I also got it because S to S claims to use much stronger welding than the competition. After finding out what it's like to have my xtherm turn into a balloon in the middle of a long tour, that peace of mind is worth a lot. Two of my xtherms delaminated/ballooned in two years, and my housemate's did too, in one year.It's very warm, extremely comfortable, a breeze to inflate and deflate, and not noisy or slippery.If you want to shave some weight and aren't exclusively winter ... MoreBest mattress I have used in my 35 years of bike touring/camping. Yes, it's a bit big and heavy, but some things are worth a bit of extra weight: superior comfort, ease of use, and knowing I won't freeze. It's only about 300 grams more than my neoair xtherm, and much better in every way.I also got it because S to S claims to use much stronger welding than the competition. After finding out what it's like to have my xtherm turn into a balloon in the middle of a long tour, that peace of mind is worth a lot. Two of my xtherms delaminated/ballooned in two years, and my housemate's did too, in one year.It's very warm, extremely comfortable, a breeze to inflate and deflate, and not noisy or slippery.If you want to shave some weight and aren't exclusively winter camping, I recommend getting the regular insulated version, and when it gets really cold, carry two 100% silk liners with you. That lets you go lighter when it's warmer. Each silkie adds 5 celsius to your equation.
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. ;)
This pad is probably the most comfortable I've had. I'm a back and side sleeper and it was great. The extra insulation was also good at keeping me isolated from the cold floor. My only gripe is the reference to being called extreme. I recently did a pretty tough outdoor excursion and this pad was completely shredded or punctured. If you are using inside of a tent, I would argue it's the best. If you want to use it in austere environment and hiking through brush, you might want to steer away. In my opinion, if it's called extreme then it should survive harsh terrain.
I feel confident that I can sleep comfortably anywhere! With my Sea To Summit quilt and down pillow, my bed sometimes feels sub par. I really enjoy the versatility of the quit and the confidence that I will be warm. The sleeping pad fits my body perfectly and being over 6ft and 250lbs, my body never touches the ground. The support from the pad is amazing and comfortable in all sleeping positions. Can't wait to wrap it all up with my telos tent!
If warmth is your critical factor this pad works great. It also is contoured and works well with other sleep systems like Zenbivy sheets. My biggest complaint is how noisy this pad is. It's literally the squeakiest of all the various pads I've owned. I even later bought a bag liner to put over the pad to reduce friction with the tent bottom and sleeping bag bottom but it didn't help much. It sounds like one of those cheap styrofoam egg cartons all night long. But it is warm and keeps you off the ground high enough to not feel rocks and roots. I think if the surface was flat rather than dimpled, it would be much quieter when pressure is applied.
Slept on uneven mix of snow and rocks. The pad made it all feel the same and I couldn't tell the difference! Comfortable and warm. You can sleep on your side, although it isn't as comfortable as a regular mattress. I'll be taking it on a 3 week backpacking trip. For all those nights of sleep, I consider this to be worth the price. Packs down well and easy to setup. I'm 6'4 and got the long pad. My feet didn't overhang the pad.
| Sea to Summit Ether Light XT Extreme Rectangular | Regular - Wide |
| R-value | 6.2 |
| Thickness (cm) | 10.0 |
| Length (cm) | 183 |
| Weight (grams) | 950 |
