The Knotty Tiger Ice is a handheld roller ball massager that pairs the comfort of massage with cold therapy to help reduce inflammation. This is a win-win to relieve muscle soreness. This knot buster fits comfortably in the palm of your hand allowing you to control the pressure and reduce fatigue in hands and fingers. The metal roller ball stays naturally cold (much colder than you would think). Kick it up a notch by placing it in the freezer prior to use. 2.5" massage surface.