With all the great features the PhD Run Ultra Light Micro sock has to offer, it wouldn't be surprising if the latest technology was hiding in your sock drawer. The Indestructawool technology gives you a longer life, while the 4 Degree system provides a performance-supporting fit. Plus, Shred Shield technology reduces toe abrasion. It's breathable, comfortable and designed to take you one step further.
With all the great features the PhD Run Ultra Light Micro sock has to offer, it wouldn't be surprising if the latest technology was hiding in your sock drawer. The Indestructawool technology gives you a longer life, while the 4 Degree system provides a performance-supporting fit. Plus, Shred Shield technology reduces toe abrasion. It's breathable, comfortable and designed to take you one step further.
in 2 offers
The lowest price for Smartwool Phd Run Ultra Light Micro Socks - Black Extra Large right now is $29.95 at Summit Gear.
The all-time low was $29.95 on 30 July 2025. That's the lowest price we've ever tracked — a great time to buy.
Prices last updated 14 May 2026.
Smartwool Phd Run Ultra Light Micro Socks - Black Extra Large
With all the great features the PhD Run Ultra Light Micro sock has to offer, it wouldn't be surprising if the latest technology was hiding in your sock drawer. The Indestructawool technology gives you a longer life, while the 4 Degree system provides a performance-supporting fit. Plus, Shred Shield technology reduces toe abrasion. It's breathable, comfortable and designed to take you one step further.
With all the great features the PhD Run Ultra Light Micro sock has to offer, it wouldn't be surprising if the latest technology was hiding in your sock drawer. The Indestructawool technology gives you a longer life, while the 4 Degree system provides a performance-supporting fit. Plus, Shred Shield technology reduces toe abrasion. It's breathable, comfortable and designed to take you one step further.
Last updated at 14/05/2026 23:59:51
Smartwool Run Zero Cushion Low Ankle Black l Size XL l Summit Gear
Delivery between 19–27 May $15
Smartwool Run Zero Cushion Low Ankle Black l Size XL l Summit Gear
Delivery between 19–27 May $15
originally posted on altitude-sports.com
I used to buy Icebreaker socks until I got a pair of Smartwood socks for Christmas. Icebreaker socks for me didn’t last very long. I love Icebreaker as I have a lot of their tops and t-shirts but i just think the socks are not as good as Smartwool. Smartwool socks are durable, comfortable and extremely breathable. I don’t have anything negative things to say about Smartwool socks. After a year, I still have the original pair I got for Christmas and they are still in great condition. I have never worn the socks for sports or for working out. I usually wear them for casual wear.
originally posted on smartwool.com
I have been a huge fan of the PhD ultralight socks in the past but wrote a bad review on these socks about 3 years ago because the design was changed and the new ones were sliding off my heel. But Smartwool has listened to their customers and changed the PhD Ultralight socks back to the best socks EVER. I have tried many other brands but none are as good as Smartwool. So I gave the PhD's another try recently and they are again the perfect sock. They stay put and provide the best comfort and support.I also love that there is not a left and right sock (I hate that so many companies think that is a good idea). Left and Right socks are sooooo annoying.Please keep making these amazing socks and please never make left/right specific socks.SMARTWOOL is doing it RIGHT.
originally posted on smartwool.com
I run a lot, I run fast and I usually run on trails - so my feet experience all strains you can imagine. Running over varying terrain, through streams and down steep tracks are all prime environments for intense friction and the inevitable blister. However, these socks are perfectly designed for this. They're thin and light which means I have great sensitivity and there's not so much cushion that it causes my feet to play in my shoes a bit. They're also pretty tight which means they don't slip around on my feet even when I'm flying down 20% grades. Their profile is low enough to look stylish in my shoes but still high enough to prevent rubbage with my shoes. Basically the perfect running/active sock I've found and I wish I could get 20 pairs. 16 mile runs with ... MoreI run a lot, I run fast and I usually run on trails - so my feet experience all strains you can imagine. Running over varying terrain, through streams and down steep tracks are all prime environments for intense friction and the inevitable blister. However, these socks are perfectly designed for this. They're thin and light which means I have great sensitivity and there's not so much cushion that it causes my feet to play in my shoes a bit. They're also pretty tight which means they don't slip around on my feet even when I'm flying down 20% grades. Their profile is low enough to look stylish in my shoes but still high enough to prevent rubbage with my shoes. Basically the perfect running/active sock I've found and I wish I could get 20 pairs. 16 mile runs with thousands of feet of elevation gain and multiple stream crossings on non-maintained backcountry trails no longer cause intense blisters!
| Sport | Running |
| Product class | Clothing |
Smartwool Run Zero Cushion Low Ankle Black l Size XL l Summit Gear
Delivery between 19–27 May $15
Smartwool Run Zero Cushion Low Ankle Black l Size XL l Summit Gear
Delivery between 19–27 May $15
I used to buy Icebreaker socks until I got a pair of Smartwood socks for Christmas. Icebreaker socks for me didn’t last very long. I love Icebreaker as I have a lot of their tops and t-shirts but i just think the socks are not as good as Smartwool. Smartwool socks are durable, comfortable and extremely breathable. I don’t have anything negative things to say about Smartwool socks. After a year, I still have the original pair I got for Christmas and they are still in great condition. I have never worn the socks for sports or for working out. I usually wear them for casual wear.
I have been a huge fan of the PhD ultralight socks in the past but wrote a bad review on these socks about 3 years ago because the design was changed and the new ones were sliding off my heel. But Smartwool has listened to their customers and changed the PhD Ultralight socks back to the best socks EVER. I have tried many other brands but none are as good as Smartwool. So I gave the PhD's another try recently and they are again the perfect sock. They stay put and provide the best comfort and support.I also love that there is not a left and right sock (I hate that so many companies think that is a good idea). Left and Right socks are sooooo annoying.Please keep making these amazing socks and please never make left/right specific socks.SMARTWOOL is doing it RIGHT.
I run a lot, I run fast and I usually run on trails - so my feet experience all strains you can imagine. Running over varying terrain, through streams and down steep tracks are all prime environments for intense friction and the inevitable blister. However, these socks are perfectly designed for this. They're thin and light which means I have great sensitivity and there's not so much cushion that it causes my feet to play in my shoes a bit. They're also pretty tight which means they don't slip around on my feet even when I'm flying down 20% grades. Their profile is low enough to look stylish in my shoes but still high enough to prevent rubbage with my shoes. Basically the perfect running/active sock I've found and I wish I could get 20 pairs. 16 mile runs with ... MoreI run a lot, I run fast and I usually run on trails - so my feet experience all strains you can imagine. Running over varying terrain, through streams and down steep tracks are all prime environments for intense friction and the inevitable blister. However, these socks are perfectly designed for this. They're thin and light which means I have great sensitivity and there's not so much cushion that it causes my feet to play in my shoes a bit. They're also pretty tight which means they don't slip around on my feet even when I'm flying down 20% grades. Their profile is low enough to look stylish in my shoes but still high enough to prevent rubbage with my shoes. Basically the perfect running/active sock I've found and I wish I could get 20 pairs. 16 mile runs with thousands of feet of elevation gain and multiple stream crossings on non-maintained backcountry trails no longer cause intense blisters!
Long-distance runner here. I own several pairs of these socks and wear them on all of my runs. I've used them heavily for over a year, including competing in a couple of marathons, and all I can say is they've really stood up to the test so far. All pairs still look and feel brand new and are just as comfortable as when I first put them on. I also did not experience any "slippage" that other commenters reported. Perhaps it's just a sizing issue.
Disclaimer: Always try out shoes before you buy - individual foot size and measurement can vary greatly. Good thing you're buying from The Running Room and can always visit a retail location!The Hoka Mach 5 is a very comfortable, speed-oriented daily trainer that can double as race day shoes. They're not as propulsive as carbon/nylon-plated shoes, but at the same time offer more stability and comfort, making them great for speedwork training or just everyday runs. They're also priced aggressively for this role. Fit-wise they feature the typical Hoka low heel drop and wraparound comfort with oversized outsole that prevents rolling ankles. The upper mesh is very porous (you can practically see your foot through the mesh) so they ventilate very well, but in wet ... MoreDisclaimer: Always try out shoes before you buy - individual foot size and measurement can vary greatly. Good thing you're buying from The Running Room and can always visit a retail location!The Hoka Mach 5 is a very comfortable, speed-oriented daily trainer that can double as race day shoes. They're not as propulsive as carbon/nylon-plated shoes, but at the same time offer more stability and comfort, making them great for speedwork training or just everyday runs. They're also priced aggressively for this role. Fit-wise they feature the typical Hoka low heel drop and wraparound comfort with oversized outsole that prevents rolling ankles. The upper mesh is very porous (you can practically see your foot through the mesh) so they ventilate very well, but in wet weather will be soaked very quickly.Overall, they exceeded my expectations (coming from Hoka Clifton 8). They are just as comfortable and takes less effort to run with, thus make my runs faster.
I use these socks for my workouts and running. I like everything about these. The zero cushion is the most comfortable for me, especially where I live in Bangkok Thailand. I love the cut as they sit below the ankle and the top of them sit at the top of my gym and running shoes, so they're very minimal. They take longer to smell than normal cotton socks, so I can rewear them before washing. And they last ages - I just bought several of them to replace some that are around 5 years old. I'll keep coming back. #sweepstakes
Smartwool socks shrink in the wash. I would normally get a size large but after a couple washes Smartwool socks are painfully tight on my toes. I try stretching them out to make them longer but it doesn't work. So now I buy extra large because these shrink down to the correct size. Problem solved. Except with these zero cushion socks. Even the extra large are small and are shrinking up to be too small. The cushioned low ankle socks are great, just get one size larger. These need maybe two sizes larger. Unfortunately, xl is the largest.
These socks made me realize that I didn't come this far in life to wear poverty socks. After wearing these I'm never going back to anything else. My initial hesitation was assuming that my feet would get too hot and sweaty because wool is for staying warm in the cold, right? Nah. These wick moisture like no one's business. I wear these in Florida daily now and they keep my feet cool and comfortable. When I take my shoes off, my feet are not sweaty.Some reviewers complain about these socks slipping off. I haven't experienced that while walking, running, standing, lifting weight or any other activity I've engaged in. I wear 10.5-11 size shoes and bought a size large. They are a good fit.One particular thing I wanted to experience for myself is the claim people ... MoreThese socks made me realize that I didn't come this far in life to wear poverty socks. After wearing these I'm never going back to anything else. My initial hesitation was assuming that my feet would get too hot and sweaty because wool is for staying warm in the cold, right? Nah. These wick moisture like no one's business. I wear these in Florida daily now and they keep my feet cool and comfortable. When I take my shoes off, my feet are not sweaty.Some reviewers complain about these socks slipping off. I haven't experienced that while walking, running, standing, lifting weight or any other activity I've engaged in. I wear 10.5-11 size shoes and bought a size large. They are a good fit.One particular thing I wanted to experience for myself is the claim people make saying that these socks can be worn multiple times without issue. Initially I thought it would be kind of gross to rewear socks but that claim is true too. You can wear these multiple times without laundering and there is no smell. My wife has a nose of a bloodhound. She can probably locate truffles buried a mile deep five counties away, better than the best trained pig can find a truffle in front of it's nose. Not a peep from her about these socks so now I'm a believer too.The socks don't maintain their aesthetics after you wear them. They start pilling after you wash them, even on a gentle cycle. I think it's to be expected but worth mentioning. It doesn't bother me.I bought two pairs to try out. Liked them so much I now own 7 pairs a few weeks later. Will buy more. Just started wearing them so no experience with the warranty, but time will tell. I'm usually gentle with things, never had to warranty any item I've owned. Maybe I've been lucky.
I'll make it really simple for you to understand. I buy these socks, 20 pairs, at a time & I have been doing this for several years. They are the only socks I wear. I run upwards of 20 miles/week in them and when I'm not running, I have them on then too. I typically get 18-20 months out of the 20 pairs. For reference, that's way greater durability than any other sock I've ever owned.#sweepstakes
These socks are my new favourite for warm or cold day activities. They are especially perfect for warm weather runs or hikes with their perfectly placed venting, adequate cushioning and low cut profile. I’m in the process of replacing all of my regular Cotton socks, and almost all of my low cut ones i now have are these. Highly recommended.
| Sport | Running |
| Product class | Clothing |
