Key takeaways

• Fantastic rechargeable hand warmer with a wide range of temperatures that also acts as a great emergency power bank.
• This unit is water- and dust-resistant, making it perfect for outdoor use.
• The unit is rather chunky, and you feel it in a pocket.

$39.99 at Amazon

I spend a lot of time outdoors, and there was a time when I could endure the UK weather with just jeans and a T-shirt. But as I've gotten older, I've come to appreciate a few more comforts -- a little warmth goes a long way.

Also: The best power banks you can buy

Recently, I've been testing rechargeable hand warmers, and to be honest, most of them are junk. Some were dead on arrival, others failed after a few hours, some had absurdly short runtimes, and others got dangerously hot. I've found a few good ones, but they're rare. What I've been searching for is a hand warmer that combines fast USB-C charging, water resistance, power bank functionality, and the ability to handle extreme cold.

I've finally found one that ticks all the boxes -- and more: theOcoopa UT4 Extreme rechargeable hand warmer . 

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Ocoopa UT4 Extreme rechargeable hand warmer

The UT4 Extreme looks like a chunky, palm-sized power bank with a 10,000mAh capacity. It features a USB-C port that supports 18W input (recharging the unit in about 3 hours) and 22.5W output for gadgets.

details

View at Amazon

While these specs are fairly standard for power banks, they're good enough for a couple of smartphone recharges. I see the power bank feature as more of an emergency backup than its primary function.

The unit is water- and dust-resistant to IP56 standards, meaning it's protected against harmful dust and strong water jets from all directions. A rubber flap covers the USB ports, making it ideal for outdoor use. 

There's also a built-in flashlight with an SOS mode for emergencies. The device is encased in a durable shell made of metal, polymer, and rubber, which allows it to withstand knocks and bumps. 

It even comes with a knotted paracord lanyard that's both neat and practical.

It's a rechargeable hand warmer

The UT4 Extreme's standout feature is its ability to turn battery power into heat -- something you don't want your average power bank to do! It offers three heat settings:

• Gentle heat: 16 hours runtime (~42