Winter warmer: The carbon fiber heated insoles can be heated to 50°C - they are soft and comfortable with rapid heating. USB rechargeable: Includes a USB charging cable which can be connected to your computer, power bank power supply or adapter power supply. Two size options: Adult UK size 2.5-6 | Adult UK size UK 6-9 | (simply follow the lines and cut the insoles to your desired size). Heated insoles: Warm up with a toasty pair of heated insoles. Washable: These insoles can be washed to keep them clean and fresh. Suitable for: Place inside your shoes, boots, wellies or slippers for wonderfully-heated feet! | USB Rechargeable Heated Insoles - UK 2.5 | Wowcher