Coldpacks, chemical agent that reacts upon contact generating and endothermic reaction.
More simply, you crack up this plastic bag, like a glowstick, and becomes ice-cold. In Cata it could be use to cure traumas or lowering body temperature in case of influenza.
Hotpacks as for the above but will produce heat instead, may be used to restore frostbitten bodyparts or to keep the body warm while sleeping.
