Hot Compress: minor muscle, rheumatic pain, stiffness and muscle spams, arthristis, sciatica ,stain of lumbar muscle, menorrhalgia etc.

Cold Compress: Contusions, minor burns, trauma, headche, scald, fever, sunstroke, sport injury etc.

Cold Compress:  put it to the freezer for 5 mins, it can keep cool for 30 mins

Hot Compress:   1.flex metal disk until crystals form,and the gel will then generate instant heat for up to 30 mins. 2. If want to reuse, and put it to the boiling water for 5 mins, and it will be heated fully.