Reusable Heavy Duty Cold Pack Round 10 Black Urethane Omega Zinc Tapes smooth and refreshed 8975 smooth and refreshed You can freeze or microwave the large gel pack to the preferred temperature Provides up to 30 minutes of cold therapy * Clay inside urethane outside *Institutional grade packs are made of durable heavy duty urethane exterior which can be chilled to a lower temperature than other packs and a bentonite clay interior * Chilled pack should be wrapped in towel before applying to treatment area * Notice to California Consumers: WARNING: This product contains chemicals known to the State of California to cause cancer and birth defects or other reproductive harm *