"Luke Warm" Disposable Heat Packs are produced with our special technology and marketed with our trademark registered in Taiwan. Contents: charcoal, water, ferric chloride, vermiculite, salt, non-toxic, non-flammable. They are available in three different packages: single large, twin small, and twin small in horseshoe package. Twin small in horseshoe pack is only for use with ski glove, mittens, parkas, jackets, ski hats, ordinary gloves, shoes, and the like to help keeping warm, for compress on joints, muscles and tendons, and for rehabilitation in medical treatment.