These USB heated slippers foot warmers are made of super soft flannel fabric and have 3 temperature settings. They effectively relieve chronic pain and increase blood circulation. It's a thoughtful gift for family and friends in winter. Care tips: machine wash or wash in cold water before use. Features: 1. Heated Slippers Foot Warmer: Protect your feet from low blood circulation, arthritis, and cold floors. In addition, this electric heated foot warmer could effectively relieve muscle, and chronic pain, increase blood circulation, and relax and warm the legs. 2. Three-speed Temperature Adjustment: Red high temperature is about 55 , blue medium temperature is about 45 , green low temperature around 35C, adapt to the needs of different groups of people. 3. Super Soft Fabric: Heats just in a few seconds and is consistently warm for your cold feet and sore muscle, made of flannel fabric, and provide you extreme care and comfort. 4. Winter Thoughtful Gift: The heated shoes are a thoughtful gift for your family, friend, someone you care about, and so on. 5. Care Tips: It is recommended to machine wash or wash in cold water. After washing, please dry it before use. Specification: Material: Flannel Product Color: Grey, Yellow, Blue Product Size: 36-40: Length: 27cm, Diameter: 11cm, Height: 7cm, Shoe Mouth Diameter: 9cm 41-45: Length: 30cm, Diameter: 11cm, Height: 8cm, Shoe Mouth Diameter: 9cm Product Weight: 160g, 170g Package Included: 1 Pair x Heated Slippers