USB Foot Warming Shoes B Model:RV-32 1: Safety: Adopt high technology exothermic material and apply low voltage of 5V, safe and reliable. 2: High thermal efficiency: Under ambient temperature 5??-10?? indoors, the temperature of this series of products can reach around 35?? which is comfortable and warm for body in a short time. 3: Rapid temperature rise per unit time: it can reach target temperature for 5 minutes only. 4: Comfort and convenience: soft and comfortable, move easily, it shall become portable home slipper only by opening zipper and taking out the heating element inside. 5: Beautiful style design: the soft and comfortable fabric can make you or your family feel fashion and warmth immediately.