Features:1.To Activate - Remove warmer from outer package, shake to activate. Warmer heats up in 3 minutes. If heat decreases, expose warmer to air and shake. After use, dispose with regular garbage. Ingredients will not harm the environment.2.Quick Heating: Unlike other foot warmer that takes about half an hour to heat the insoles, it only takes 3 minutes for complete heating of our foot warmer.3. When to Use: Tailgating at events, outdoor sporting events, hunting and fishing, camping and hiking, working in the yard, jogging or taking your pet for a walk. Convenient, compact, portable.4.Long-Lasting: Last about 12 hours at approximately 127 degrees Fahrenheit.5.All Sizes: We have different size, covering all you need for different foot sizes, 2 packs.XS for kids, insole size about: 20.5cmx7cmS for women, insode size about: 23cmx7.8cmL for men, insole size about 25cmx8.5cmXL insole size about 26cmx8.5cmincludes:2 pair x insoles