Abstract: A heat pack using supercooled aqueous salt solution that resists premature activation at low temperatures is disclosed. The heat pack comprises two sheets that are bonded together to form a laminated sheet. The heat pack has a first and second compartment. A frangible seal separates the two compartments. One of the compartments contains a supercooled aqueous salt solution. The salt solution contains 15 to 25 percent glycerin by mass.

Abstract: A thermotherapeutic pad includes a sealed envelope having a top layer of plastic and a bottom layer of textured plastic. The top layer of plastic and the bottom layer of textured plastic can be heat-sealed together. The bottom layer of textured plastic has an outer textured surface and is more thermally insulative than the top layer of plastic. A plurality of gel beads and liquid are contained inside the sealed envelope. The bottom layer of the pad can be placed against the skin or clothing to provide thermal therapy. Baffles can be provided inside the sealed envelope to promote even distribution of gel beads.

Abstract: A thermotherapeutic pad for applying heat or cold to a body part. The pad has a material for releasing or absorbing heat and a thermally conductive envelope for containing the granular material. The pad also has a holder for removably holding a cold pack adjacent to the envelope. The thermotherapeutic pad may provide heat by heating the material and placing the envelope against the body part, and the thermotherapeutic pad may absorb heat by placing a cooled cold pack into the holder and placing the portion of the pad comprising the cold pack against the body part.