Amazon.com: ObboMed MF-2320M Far Infrared Carbon Fiber Heated Foot Warmer/ Boots/Slipper, 12V 20W – Far Infrared wavelength 8-15 μm (Health Range: 4-14 μm), Auto Off, Size M: #41 (fits Foot up to 41) :
XCMAN Portable Shoe Dryers and Boot Dryer for Ski Boots,Work Boots,Rain Boots,Tennis Shoes,With Integrated Fan and Heater-Ultra Silent | 12V Cigarette Lighter Adapter and AC/DC(100V~240V) Adapter| US - Walmart.com
Teeter EZ-Up Gravity Boots with Adapter Kit – Total Fitness USA