Specification: Fabric Cotton + polyester + spandex Power supply 3 x AAA Batteries (Not include) Size 30 x 21cm / 11.81 x 8.27inch Features: Electric warm socks, cotton material, breathable Water absorbent, quick-drying, elastic thickened, electric modules using ultra-thin, soft. Electric heated socks for chronically cold feet. Cushioned strengthened rear area and toe, and recessed warming component enable concentration to warm in the toe to shield your feet from getting cool Battery powered, safe and reliable. Built in heating elements extended along forefoot to promote blood circulation. Package Included: 1 x Pair heated socks 2 x Lithium battery box