Product Name: Insole Warmer Model NO.: W203 Product Description FEATURE:1) Material: two sides non-woven fabrics2) Size: M 220mm Length / L 250mm Length3) Color: brown4) Air-Activated5)Average temperature:45°C6)Peak temperature: 48°C7)Heating time: 7 hours8)Weight:M 56g±2g/Pair; L 68g±2g/PairMAIN INGREDIENTS:Iron powder, Salt, Activated Carbon, Water, Sodium Polyacrylate, Wood powder, VermiculiteINSTRUCTIONS:INSOLE WARMER PAD is the perfect solution for cold feet. It is designed to function in the low oxygen environment for boots and shoes. Simply place Foot Warmer insoles inside a pair of closed-toe shoes or boots. Foot warmer insoles are designed to use inside the shoe or boots where oxygen is restricted. Do not use in ventilated type footwear. and enjoy more than 7 hours of warmth , with an average temperature of 45°C and a peak temperature of 48 °C.