Heatmax ToastiToes Insole Foot Warmers provide you warmth and freedom to endure cold climate situations. This product is used by professional athletes, outdoor sportsmen, spectators, skiers, construction workers, and by those who want safe, convenient, concentrated warmth. INSTRUCTIONS: Up to 9 Hours of heat Open outer film and remove warmer, only when ready to use. Peel away the protective backing and immediately place on the outside of sock on sole of foot (not on instep, ankle or top of foot). Use only inside shoe or boot. After use, remove immediately and dispose of warmers in regular garbage. » Read more: HeatMax ToastiToes Air Activated Insole Foot Warmers With Adhesive