Extra warm: Feel the heat quickly and evenly up to 50°C. Suitable for: Slip inside your shoes or slippers for warm and toasty feet - ideal while sitting in the office or working from home. USB: Enjoy the warming function while the insoles are connected to a power source such as your computer or portable power bank (the included cable is 1.5 metres long). Heated insoles: Get extra toasty toes with a pair of heated insoles. Two sizes: UK adults size 3-6 | UK adults size 6-9 (simply cut the insoles to your desired size). Washable: Can be surface cleaned to keep them fresh, but not to be submerged in water. Usb Heated Insoles | Living Social | Living Social