This Therm-ic set includes a pair of 3D heated insoles and 1 pair of C-Pack 1300B batteries. Heated insoles with an anatomical 3D shape for optimal support Stable support for better pressure distribution Ultra-thin heating elements for optimal foot temperature C-pack 1300 Bluetooth batteries provide up to 13 hours of heat Equipped with the Bluetooth® function, they will allow you to manage your heating remotely via a smartphone: Thermic Heat Control application INSTRUCTIONS FOR USE Remove the old sole from the shoe Cut the HEAT 3D to the desired size at the marked places. Be careful not to cut the power cord and heating element in the area under the forefoot. Place the HEAT 3D insole in the shoe Run the power cord up the heel along the calf Connect the power cord to the Therm-ic C-PACK batteries