I found the ultimate travel accessory during the cold winter season – and it's fairly cheap

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.

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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: the Ocoopa UT4 Extreme rechargeable hand warmer. 

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°C/108°F)
• Medium heat: 12 hours runtime (~47°C/117°F)
• High heat: 9 hours runtime (~53°C/127°F)

Holding the boost button for three seconds activates a high heat boost mode, raising the temperature to 58°C/137°F but reducing runtime to 6 hours.

The unit is quite innovative in the way it heats up. It cycles the heaters on and off continuously, so you can see the temperature oscillate up and down by about 10°C/50°F over a few seconds. 

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There are heating elements on both sides of the hand warmer, a big one on the top and a smaller one on the reverse side.

The hand warmer comes with a carry pouch, which is great for transforming it from a direct heat source into a more ambient one. I recommend using the pouch for higher heat settings, as temperatures above 60°C/140°F can be dangerous. According to ASTM C1055 (the Standard Guide for Heated System Surface Conditions that Produce Contact Burn Injuries), 60°C/140°F is the maximum temperature the average person can touch for up to five seconds without sustaining irreversible burns. 

If you have small hands or pockets, this hand warmer might feel a bit chunky, but you can’t have it all, and this one does offer one of the longest battery runtimes that I’ve come across for a hand warmer. 

ZDNET’s buying advice

The OCOOPA UT4 Extreme is a really neat, versatile, durable, and reliable hand warmer that also doubles as a power bank, flashlight, and torch. Whether you’re braving the outdoors or just need a little extra warmth at work or on your travels, this gadget is a fantastic companion. And at only $40, it’s a great price for a hand warmer alone, let alone one that doubles as a power bank and flashlight.