Temperature: Reaches a max temperature of 50 degrees celsius. Usage: Plus into a USB slot, heat and the shoes will stay warm after reaching required temperature - recharge to heat again! Colour options: Choose from either grey or pink. Slippers: Grab yourself a pair of heating slippers. Size options: Choose from 2 sizes - womens (UK 2-6) or mens (UK 3-7.5). Cosy: Slip into these super comfortable slippers - sure to keep your feet warm and toasty! | USB Rechargeable Heating Slippers - Black - UK | Wowcher