Yaktrax Disposable Hand Warmers are a superior source of natural heat that keep hands warm when the temperature gets cold. Once opened, these odorless and environmentally-safe warmers begin working within minutes, providing up to 8 hours of steady warmth. Yaktrax Hand Warmers contain natural ingredients including iron powder, water, salt, activated charcoal, and vermiculite. Yaktrax Warmers are ideal for keeping warm when camping, hunting, fishing, skiing, athletic events, and more. Dimensions per warmer: 3.5 x 5 x 0.25 inches.