Reusable hot/cold temperature pack

A temperature pack, comprising:

• a flexible outer casing;
• a gel contained inside said outer casing, said gel responsive both to heating and cooling externally applied to said temperature pack so that said gel becomes heated or cooled depending on whether heating or cooling is applied to said temperature pack and remains in a heated or cooled state during a prolonged continuous hot or cold therapy period after the externally applied heating or cooling is removed but remains in a gel state whereby said gel provides cushioning to said temperature pack even when said gel is heated or cooled;
• and
• a temperature cell contained inside outer casing and disposed in said gel, said temperature cell having a fluid filled chamber wherein the fluid is also responsive both to the heating and cooling externally applied to said temperature pack so that said fluid becomes heated or cooled and remains in a heated or cooled state during the prolonged continuous hot or cold therapy period after the externally applied heating or cooling is removed such that at least the prolonged continuous cold therapy period is at least about two hours.