The newcomer on the scene is the reusable chemical hand warmer. These are gel pockets filled with sodium acetate, dissolved in water, and a small, thin metal disk. When you bend the disk back and ...

Since the whole point of this device is for it to get warm to the touch, I was glad to see they had the presence of mind to clad the Go Warmer with metal. But make no mistake, at just 0.5 mm thick ...