DeFeet Officially Introduces Tougher-Than-Kevlar Cooling UnD-Ice and Armskins Ice Garments

We first saw this fabric more than a year ago as a prototype material which DeFeet had fashioned into various garments, including a jacket. Goading us to try it on in the middle of summer, DeFeet president Shane Cooper smiled big as our jaws dropped.

Made of Tuf ‘n Lite Cool Fiber, the new UnD-ICE and Armskins ICE actually cool the skin as wind blows over them. Even better, they provide remarkable abrasion resistance, helping to protect your skin in the event of a wreck. In fact, the textile manufacturer says it’s tougher than commonly used aramid fibers like Kevlar.

UPDATED: New info added below about cooling effect and how it works.

But does it work? Well, I can’t vouch for the abrasion resistance, but I’ve been riding with one of the UnD-ICE undershirts this summer and it’s like air conditioning. Put your curiosity on ice after the break…

DeFeet UnD-Ice cooling cycling jersey undershirt made of Tuf-n-Lite protective fabric

Designed for 80º to 100º F days, the ICE garments pull heat away from the skin with remarkable rapidity. In fact, they feel cool to the touch even when you’re not moving. Introduce wind (read: movement on the bike) and you’ve got something that automatically and continually chills you.

DeFeet Officially Introduces Tougher-Than-Kevlar Cooling UnD-Ice and Armskins Ice Garments

Cooper had this readout handy along with some gloves made from the material versus Aramid. It works by combining a synthetic wicking fiber that pulls moisture from your skin and another that actually feels cool to the touch.

DeFeet Officially Introduces Tougher-Than-Kevlar Cooling UnD-Ice and Armskins Ice Garments

In real world use, the undershirt rocks. Defeet recommends using it with a full zip jersey, and here’s why. When it’s bundled up under a jersey, particularly a tight fitting road jersey, the magic doesn’t happen nearly as well as it could. Unzip the jersey and let some fresh air in and *pow* it’s downright chilly. On a couple of warmer (read: stupid hot) rides, I remained fairly comfortable while others were complaining profusely and visibly overheated. Walk into an air conditioned room after the ride and you’ll get goosebumps. It’s crazy.

UPDATE #1: DeFeet’s tech guy sent over some documents and called us with a better explanation of how the material cools and feels cold. Basically the material is super dense and has virtually no ability to retain heat. So, it quickly draws heat from the body and dissipates it to the outside air, which is why it feels cold to the touch. That’s also why it really needs airflow to achieve effective cooling. They did mention that while they performed some basic temperature testing that showed slightly cooler skin temps on athletes using it, they stopped short (likely for budgetary reasons) of doing formal scientific core body temp testing to prove a benefit. Anecdotally, all test athletes said they felt cooler wearing it and their “basic” data backed it up. I concur, it made me feel cooler on hot days, particularly when I had my jersey unzipped or all the way open.

DeFeet Armskins-Ice cooling cycling arm warmer covers made of Tuf-n-Lite protective fabric

The better application, in my opinion, is the Armskins ICE. Even better, DeFeet should make a jersey from the material for really hot days. Putting the material in full contact with the wind would maximize the benefit of this amazing material. Given that body heat management can be a major performance factor, this could be big.

UPDATE #2: The material has been documented to have an SPF 50, making the Armskins in particular an even better piece to add to your collection.

UPDATE #3: Technical Document (click to enlarge):


  1. I heard somewhere that this “new” material is just the same Olefin that Swiftwick has been using for a couple years. Any truth?

  2. I hope they make a long sleeve version for motorsports. This would work great under my leathers at Thunderhill this weekeend.

  3. I own one of these tops and can tell you after a lot of riding in 80+ degree temps that it DOES NOT WORK. This is a $100.00 undershirt…if it were less expensive I would not be so critical but a $100.00 investment in an undershirt better really work and this does not live up to the hype.

  4. Without having specs for Craft products and the DeFeet shirt next to each other for comparison, it’s impossible to say whether or not there’s “nothing new here.” Without specs or other data to prove otherwise, it’s like about Boeing’s new 787 that “Cessna’s been making Cessna 152’s for a while. Nothing new here.” Without knowing anything about the 787, having heard no news reports, a person could just as equally think that Boeing’s plane is obviously the same as a 152 since they both have engines and can carry passengers. Craft doesn’t say anything about abrasion resistance of their Cool Tees.

    An undershirt (or jersey even) that cools more effectively AND is abrasion resistance seems like a winner. I don’t see a jersey being a real option. Such a jersey would have to be tight to optimize cooling and to resist snagging (or “snatch”) when sliding along tarmac. Such snatch can lead to nasty injuries.

  5. All, post updated slightly with info about the cooling effect and how it works.

    Eric, check Tuf ‘n Lite’s website (link in article), they make apparel for various activities. The real benefit of this material comes when there’s airflow over it. Under your leathers and you may not feel it nearly as much as if you unzip the jacket.

    Robin, based on my use of the undershirt, a normal roadie-fit jersey would be appropriate…it wouldn’t have to be inordinately tight to reap the benefit.

    Sambo, the first run was already sold out. They’re getting in another 250 pieces soon which will be their last run for this season. No need to sell them in the cool weather.

    MTW, we received a PR photo and name of Craft’s clothing that claims similar benefits, but when we emailed them to get more info on how it worked, we got nothing in response. By contrast, DeFeet’s folks returned our call within minutes. Craft makes fine clothing, I own several pieces and love it, but we didn’t have enough info to do a good post or comparison.

  6. we’ve had these at Boone Bike in Boone, NC since June. and i can agree – they do work. you do have to unzip your jersey to get the effect. and the armskins actually feel ‘cooler’ on the shelf than the baselayer. rad!

  7. I’m very sad to report that this fabric doesn’t cool you off in ANY WAY. I bought the DeFeet Armskins ICE and thought they might be the answer to my hot-blooded prayers. I bike commute every day in the summer despite not loving the 80-100 degree heat and high humidity in Minneapolis. I was very excited to try the Armskins, as they are touted as a miracle fabric that cools you off (from some accounts “almost too much”).

    This is poppycock! The armskins not only did NOT cool, they actually WARMED. They are pretty much like wearing any armwarmers made from polyester. I stopped short of returning them, since I may decide to use them for fall and winter. Save your money and skip this product.

  8. I wonder if these only work in dry heat as evaporative methods of cooling don’t work in high humidity climates.

    Can we get a response from DeFeet?

  9. I’m really torn on whether or not to try out this product. If it uses evaporative cooling, then low humidity is needed for adequate cooling. Higher humidity and material no matter what it is will evaporate slower. Is this material made magic polar snake oil? I would like to see some results or testimonials from dry climates as well as humid climates. I race long distances in velomobiles and can direct some airflow on myself but the interior of the velo can become very humid and my jerseys in warmer weather are always soaked. I get out of the velo and the surrounding air chills me. I would be glad to try out the product if there wasn’t any problems in returning it due to the possibility of false or partially truthfull advertising. I don’t mind spending larger amounts of money as long as the product actually does what it claims.

  10. I would say buy and try $45 retail. If they are not cool, you have a spare set of warmies.

    I am buying the Zoot flavored ones to try, $30 and they have more sizes.

  11. I can tell you that the UnD ice is awesome. Keeps you cool on even the 95+ degree days, plus in the crash it help protect me from road rash on the back, where on the shoulders I did get road rash. There was a big hole in my back of my jersey, but none in the UnD ice and no road rash on the back. I ordered another one to replace the slightly damaged one.

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