LONG-LASTING HEAT: Air-activated, unscented, and ready to use. Heat duration lasts up to 18 hours. Max temperature: 165°F (74°C); Average temperature: 142°F (61°C). OPEN AND GO: Simply open package and shake. Reaches max temperature in 15-30 minutes. No batteries, no charging, works anywhere. If the temperature begins to decrease, expose warmer to air and shake. OUTDOOR: Perfect for skiing, snowboarding, hunting, construction work, outdoor sports, and winter commuting. Stays warm from morning to evening. SAFE & NATURAL: Made with iron powder, water, vermiculite, activated charcoal, salt, and high water absorption resin. TSA-approved for flights. Odorless, non-toxic, eco-friendly disposal. WARMER SIZE: 4.8" x 3.7" x 0.1"; BOX SIZE: 9.75"L x 6.5"W x 7.3"H.