Material: Iron powder, water, vermiculite, activated carbon, salt, highly absorbent resin; lasts over 104°F (40°C) and over 20 hours. (Maximum temperature 149°F (69°C), average 148°F (63°C)). For commuting to work or school. A fun and fashionable way to make every day. Warm in the house and in the room. Unlike traditional chiros, it looks fashionable and cute.