"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. Single Large pack is used for take warm at winter, in place of avoid fire and labor at place of freezing, and ascend height mountain, or bivouac et, alleviation for articulation.