Heat Factory Adhesive Toe and Foot Warmers Pack of and long-lasting warmth to your feet for 6+ hours Toe Warmers specifically designed to heat up restricted air when worn on socks in shoes, boots, ski boots, slippers and more Safe, non-toxic and odorless heat warmers are pre-mixed with a mixture of iron powder, charcoal, salt and vermiculite Adhesive backing adheres to outside of sock underneath the toes