Need a boost of warmth for your freezing toes? This pack of 2 rechargeable batteries is just what your feet need. Compatible with KOMBI's Warm It Up heated socks, these 2 lithium-ion power packs can be recharged via USB-C input and USB-A output. They are easy to use and offer up to 8 hours of heating time, so you can comfortably make the most of your day spent in the cold. Plus, our KOMBI batteries come with a 1-year warranty.