The Therm-ic S-Pack 1400B stands out as the most robust battery option in its category, offering exceptional power for heated socks. With the convenience of Bluetooth technology, users can effortlessly adjust the heat settings directly from their smartphones. This battery ensures up to 16 hours of warmth, making it an ideal companion for extended outdoor activities in cold weather. Includes two S-Pack 1400B rechargeable batteries for heated socks Bluetooth connectivity allows heat level control via smartphone Offers three heat intensity levels for personalized comfort Provides up to 16 hours of heat on the lowest setting Compatible with Therm-ic Powersocks for seamless integration Comes with a USB charger for simultaneous charging of both batteries Technical FeaturesHeating time level 1: up to 16 hours Heating time level 2: up to 8 hours Heating time level 3: up to 5 hours Charging time: 5-7 hours Compatibility Powersocks Heat Men ND Powersocks Heat Women ND Powersocks Heat Uni ND Powe