OccuNomix Hot Rods™ Universal Toe Warmers Heat Pack is designed to fit comfortably under toes in shoes, sneakers or boots. Simply open to activate and position in shoes, at toes for warmth. It reduce the risk of frostbite, numb, frigid or aching toes. It warms up within 2 min and last up to 5 hrs once activated. Temperature ranges from 115 to 124 deg F.