Commercial heat packs (containing iron and water, or supersaturated sodium acetate) and cold packs (various ammonium salts) can be used to show exo- and endothermicity. Heat packs that contain iron ...

A reusable hot pack made of a supersaturated sodium acetate solution that crystallizes spontaneously once triggered by a metal piece releases heat. A balloon filled with hydrogen gas also releases ...

Helps muscle recovery for knees, back, shoulders, hip, or neck. Alternative to Hot packs for pain relief : Used by thousands of physical therapists and medical pros for acute and chronic muscle ...