This is the stainless steel roller that combines cryotherapy and traditional massage to help numb pain and reduce inflammation after an injury or workout. The top of the unit unscrews, allowing the massage ball to be removed and placed in a freezer to chill its 3.4 oz. of cooling gel. Two hours in the freezer provides the ball with up to six hours of cryotherapy. Ideal for treatment of back pain, plantar fasciitis, and sore muscles, the friction-free ball glides comfortably over the skin and cleans easily with soap and water. 3 1/2" diam. x 3 1/4" H. (1 1/4 lbs.)