Very simple device yet very effective!
The hand warmer actually keeps my hands warm. (It can be so hot if hold the hand warmer tightly). I bring the device with me every morning and leave the device in the car when leaving for a class. I am impressed with the hand warmer because of its battery life (14 hours as per the product description). Very easy to use because my wife is somehow able to turn on and off the device without reading an instruction. Perfect for a gift to someone who is living in eastern states where there is snow during the winter period.
Rating: 5 stars