The Relief Pak re-usable cold pack is an effective method of applying cold therapy to a localized area. Place pack in a chilling unit or freezer. Packs remain pliable and soft even below freezing. Pack maintains its therapeutic level for up to thirty minutes. Chilled pack should be applied to treatment area using either a light towel or a Relief Pack cover. Terry cloth Relief Pak Covers can withstand repeated maching washing and drying.