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Hyperice X: This high-tech cold and heat pack for your knees might blow your mind

This remarkable battery-powered $399 sleeve fits over your knee and delivers both iceless and waterless cold and heat therapy in a single product.

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The Hyperice X costs $399 and ships Sept. 20 in limited quantities.

David Carnoy/CNET

Don't be surprised if you see an NBA player sitting on the bench this coming season with his knee -- or knees -- wrapped in a sleeve that's covered in what looks like mini perforated hockey pucks. That sleeve is the $399 Hyperice X, a contrast therapy device that delivers iceless and waterless cold and heat treatment with a press of a button in a companion app on your phone. I got a chance to play around with the Hyperice X in advance of its launch on Sept. 20 and it's impressive just how cold -- and hot -- it gets... and how quickly it can shift temperatures.  

The Hyperice X is the brainchild of Alex Aguiar, a former collegiate soccer player at University of California Davis who spent five years developing the product at his start-up Recover X before selling the company last year to Hyperice, known for its Hypervolt massage guns and other percussive therapy products. The idea behind it was to somehow shrink the medical-grade $18,000 Game Ready Med4 Elite contrast therapy machine he encountered when rehabbing an injury into a consumer device that was portable and could be used anywhere.

Read more: Best massage gun for 2021

Aguiar, now Hyperice's Director of Product Development, says semiconductor-based Thermoelectronic cooling or TEC has been around a long time (you reverse the current to get heat), but the technology is inherently power hungry. The challenge was to create a compact, energy-efficient system that could be powered by a battery that wasn't huge. The secret is in those mini perforated hockey puck modules, which have fans and temperature sensors built into them, and the rechargeable Tesla battery attached to the top of the sleeve. 

"This is the most innovative cold and heat therapy product that's ever been made because it is not reliant on any ice or water," says Aguiar.

At its max settings, Aguiar says the Hyperice X can cool at a temperature as low as 32 degrees and as high as 113 degrees, although your skin temperature for cooling is more like 50-60 degrees. Unlike the Game Ready Med4 Elite, often used as part of post-surgery recovery, the Hyperice X has no compression therapy mode (Hyperice also sells the less high-tech Hyperice Knee compression ice wrap and bought Normatec, which makes compression therapy products).

On battery power, the Hyperice X can cool or heat for about an hour (battery life is rated at up to 1.5 hours but that's not for the highest settings). However, you can plug the unit it in with the included AC adapter and do longer sessions so long as you're near a power outlet.

My knees are still in pretty good shape -- I've never had knee surgery -- so I can't say I used Hyperice X as a therapy tool. I did stick it on my 15-year old kid's leg after he was complaining of a little knee pain (more of a bruise) after playing a soccer match and he was shocked by how cold his skin got -- and how quickly it got cold. He ended up using Bluetooth-connected app on my phone to turn shift to more of a medium cold setting. You also use the app to do a set program that alternates between hot and cold. While it isn't cheap at $399, if you do have knee issues, it seems well worth considering at that price.

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You can set the temperature and duration of the therapy via a Bluetooth-connected app.

David Carnoy/CNET

Agular says he started with a contrast therapy device for the knee because it's easier to make a thermally efficient device for it. When I said I needed something like this for my neck and the top of my shoulders (neck and shoulder tightness are the hazards of working on computer all day), he said that Hyperice had other X devices in the works for other body parts, including the ankle and shoulders.

Hyperice has several athlete investors, including NBA players like Anthony Davis and Chris Paul along with NFL stars Patrick Mahomes and Christian McCaffrey, as well female athletes like four-time Grand Slam champion Naomi Osaka and skiing great Lindsey Vonn, who's had her share of knee operations. I suspect we'll spot more than a few athletes wearing the Hyperice X post-match in the coming months. It certainly looks cooler than having an ace bandage wrapped around an ice bag -- and it's reusable.

The information contained in this article is for educational and informational purposes only and is not intended as health or medical advice. Always consult a physician or other qualified health provider regarding any questions you may have about a medical condition or health objectives.