ActiveWrap Heat/Ice Pack-Medium (Set of 2) PROFESSIONAL COLD THERAPY These thermal packs are unexpectedly soft and flexible. Use in the microwave, hot water, or freeze in the freezer to give you total versatility of use. FDA Registered. ITEM COMES COMPLETE WITH 2 reusable heat and ice packs and 2 nylon ice covers. Measures 6"x 9" This MEDIUM PACK size is designed for use with the ActiveWrap L/XL Elbow. FOR COLD THERAPY USE Place ActiveWrap thermal packs flat in freezer with nylon pouch for minimum 2 hrs before using (small packs) or 4 hours for large size packs. IF YOU ARE USING ACTIVEWRAP Knee, Shoulder, Hip, or Back Wraps these models are equipped with our new D.L.P. design. SENSITIVE SKIN INDIVIDUALS and/or elderly patients should opt to ice with a thin paper towel or fabric between skin and the pouch.