ActionHeat 5V Battery Heated Winter Hat – Heat Beanie Fleece Lined with Water Resistant Softshell, Carbon Fiber Heating Panels, Built-in Heating Panels

Great. Its been minus 20. Also wearable indoors if its drafty, on low setting. Works on same battery as cell phone so you can charge your phone too. Looks cool. Seems to be water resistant. Help America fight the flu

This is my second favorite heating device for the winter; the first being the heated jackets. This hat is warm and lasts for a long time!

Not happy