Reusable Simple to heat or chill. Clear instructions on the pack. Reusable product. Reusable hot/cold therapy pack to help soothe muscular discomfort and help to reduce swelling and bruising. The hot pack will assist in increasing circulation with temporary relief to muscle aches back pain sinusitis or menstrual cramps. The cold pack will assist in temporarily reducing swelling toothache headache and fever. Microwave for approximately 30 seconds or immerse in boiling water for 4 -10 minutes OR store in the freezer gel takes approximately 1 hour to freeze. Covers available. 13cm x 26.5mm