Features: 1.Made of high-quality flannel composite fabric, it is light, soft and comfortable, with good thermal insulation and long service life. 2.As a necessary warming artifact in winter, it heats at a constant temperature 50-60 to bring comfortable warmth to your feet in cold weather and drive away the cold. 3.Universal USB interface, compatible with a variety of charging devices, such as adapters, mobile power supplies, car USB interfaces, computers, etc. 4.The portable foot-warming bag is easy to operate, and can be used by connecting USB interface, without charging or self-provided batteries, which is more environment-friendly. Specifications: Material: flannel composite fabric Color: grey USB cable: 5V=1.78A10W Outlet: 1.2m Net weight: 0.142KG Product dimensions: 29*29*2.5CM Packing: 34*30*2.8CM Packing List: 1* Foot Warming Bag 1* USB cable installed on the product.