The Elasto-Gel Cranial Cap is used for treating the head and neck area with hot or cold temperatures as required. Like the other Elasto-Gel products, this can be put in the microwave for heating or in the freezer for cooling. Stays soft and pliable, even at -20 F. Will not leak if punctured. Durable; can be used over and over again.  Weight: Small/Medium-2.6 lbs   Large/X-Large-3.0 lbs