Thermal and lightweight materials to fit under jacket or use by itself. The battery powered heated jacket liner can be used with the supplied battery which is perfect for staying warm even when off the bike. For extended use, the jacket liner can also be powered directly from your motorcycles battery. When more than just core warmth is needed, connectors at the end of each arm allow for easy connection to firstgears heated glove liners. Use with a compatible li-ion battery. Dc:12v, draw: (42)w.