electric heated shoes insole 1:Lithium battery or battery box 2:Can cut into a suitable size 3:Far IR heating 4: 4 ... .5/5/7.4V Lithium battery or 3AA battery box carbon fiber electric heating shoes insole in cold winter Voltage5V, 4,5V, 7 ... , let feet warm comfort in the cold winter. In the heating process, carbon fiber will produce far infrared ray, which is good ...