A Battery-Heated Hat (i.e., "beanie") can be valuable in a variety of cold environments, especially for those who have cold-ear, migraine, or facial paralysis issues. The hats contain a built-in heating panel on each side, a small battery pack that's pocketed in the back, and heat-setting and on/off buttons in front. It's reportedly safe to wear regardless of the outdoor elements, machine washable, heats up in about 30 seconds, and operates for 7-8 hours before a needed battery recharge.