Who makes a custom cold pack?
Nortech Laboratories Inc. www.nortechlabs.com Hot Cold Therapy Pack: Therma-Kool
A cold pack creates a endothermic reaction when the chemical reacts, which means that energy is taken from the surrounding, which makes the packaging cold. it is the opposite with a heat pack, an exothermic reaction is created which releases the energy into the surrounding creating the heat. Hope this helped.