Go Warmer electric hand warmer review
item is "as seen on tv"
pros
gets warm
cons
could not get the power bank function to work properly with my usb-c cell phone (could be a compatibility issue)
does not reach advertised 120 degrees, but that could be due to measuring the temp in an open-air setting. Inside of a pocket, 120 degrees would not be unreasonable to expect.
Assuming it last a few years it would be a great gift for a camper, or someone who likes to attend outdoor sports