Features: Using USB interfaces for power supply, convenient and fast, heating function can achieved by connecting to the power supply. Provide a long terms and comfortable warm foot experience. Make of Crystal lint and carbon fiber heating wire, providing a comfortable touch and wearing experience. Suitable for most people who need to keep their feet warm in cold weather. Help alleviate the icy sensation in cold weather. The heated soles can wash and reused. Note: Not machine washable. Please make surely that the power cord does not wet, and keep completely dry before use. Suitable for daily shoes such as boot, sports shoes, etc., providing comfortable heating function. Specifications: Materials: Crystal lint, carbon fiber heating wire Shoe size: 35-36/37-38/39-40/41-42/43-44 35-36 size: about 22.9x7.1cm/9.02x2.8inch 37-38 size: about 24x7.8cm/9.45x3.07inch 39-40 size: about 24.9x8cm/9.8x3.15inch 41-42 size: about 25.8x8.3cm/10.16x3.27inch 43-44 size: about 27.3x8.3cm/10.75x3.27inch Voltages: 5V Current: 2A Temperature: 40-50℃ Package Includes: 1pair Heated Shoe Insoles note: Please allow 1-2cm errors due to manual measurement, make surely that you not mind before order. Due to difference between different monitors, the picture may not reflect the actual color.