Warmthru Hotmitts: Rechargeable Battery Standard Heated Ski Mittens (2 - Medium) 4 3.7v rechargeable Li-ion batteries included + 2 battery chargers Triple the heat of comparable gloves due to 2 batteries per mitten Waterproof zips guard concealed battery pockets Luxurious padding retains heat If you suffer from cold extremities or circulation difficulties such as RAYNAUDS, try these amazing Warmthru Hotmitts