Relief from strains, sprains, tendonitis and other injuries. Perfect for covering your back. Unique strapping system securely fastens anywhere on these hot and cold packs. Two "frost-free" surfaces protect your skin. Plush surface provides slow-release treatment while the rapid-release surface provides quicker results. Non-toxic gel is biodegradable and retains therapeutic temperatures longer. Store in the freezer; stays soft and pliable. Heat in microwave.