Ideal for use on a sports injury to help reduce the pain. If a cold pack is used this will aid in reducing the swelling whereas if a hot pack is used this will assist in increasing circulation to the injured area. Older designs of this kind of product often needed a cover to prevent potnetial damage tot he skin or extreme discomfort when applied at first. This pack is made from a thicker material that is more comfortable when frozen or heated. Using a cloth, towel or similar is often still advised by professionals though.