The Hotronic FootWarmer Power Plus S3 Power Set is the perfect way to keep your feet warm this winter! Match up the S3 Power Set with Hotronic's Heating Elements installed on your favorite insoles and you've got 3 high-capacity, cold-temperature-operation, rechargeable NiMH AA batteries keeping your toes toasty. Or add the pre-wired BD Anatomic Insoles to your shopping cart too and you'll be ready to simply plug-in, attach the battery pack to your boots, and say goodbye to cold toes!We also carry the entire line of Hotronic Products!