Bests & Worsts Reviews from Amazon

I suffer from Raynaud's syndrome, meaning that my fingers turn white even at only slightly cold temperatures. I'm an avid runner and especially have trouble with my fingers going numb after a run. This hand warmer has really helped. I keep it in the car, plugged into the inverter so that the car battery recharges it while I drive. I switch it from one hand to the other to keep my fingers from going numb on the way home, or drop it in my pocket if I need to go to the grocery store on the way home. The warm metal conducts the heat to my fingers much better than holding them in front of the hot air coming out from the car heater. I haven't tried using it as a phone charger, but I could see where that function could be useful as well on long plane rides or camping trips. I first tried the Hot Snapz chemical rechargeable hand warmers, but they didn't last very long and I have yet to go to the trouble of boiling them to recharge them for a second use. This hand warmer is much more practical and effective.