They’re actually battery powered and have a remote control, if you can believe it. I never need them higher than the lowest setting and they last around 8 hours. https://www.amazon.com/Neveland-Control-Rechargeable-Electric-Settings/dp/B09JW8TWGT/ref=mp_s_a_1_3?crid=2NGRUUBU9CO56&keywords=neveland+heated+socks+for+men+rechargeable&qid=1668301881&sprefix=neveland+socks%2Caps%2C99&sr=8-3