HotHands Hand Warmers are single-use, air-activated heat packs that provide up to 10 hours of continuous warmth. Each warmer contains natural ingredients like iron powder, water, cellulose, activated carbon, and salt. When exposed to air, these ingredients react to produce heat, making them ideal for outdoor activities or cold environments. The warmers are odorless, environmentally friendly, and have a shelf life of up to four years.