Made with environmentally safe, non-toxic ingredients: iron, water, cellulose, vermiculite, activated carbon and salt * Body warmers last up to 12 hours with multiple placement options * Heat packets maintain a temperature of 135 - 156° F, and can be wrapped in cloth if they feel too warm * Little Hottis Hand warmers keep you warm all year-around. * Works best in enclosed areas such as pockets or gloves, where oxygen is restricted