The Therm-ic C-Pack 1300B (One Piece), similar to the C-Pack 1300, includes 3 manually controlled heat settings to help keep your feet warm all day long.However, fitted with Bluetooth technology, the C-Pack 1300B allows you to remotely control your heat settings via your smartphone using the Thermic Heat Control App. The app provides increased adjustability, personalization, and battery life through accessing 10 different heat levels, motion control, and eco mode. C-Pack batteries are suitable for use with Therm-ic Insoles Heat Flat, Heat 3D and Heat Kit range only.