TRATAC ActiveRoll - High Intensity Fitness Vibration Foam Roller - Optimized for Back Pain, Muscle Pain and The Best Recovery, Pain Relief Roller &hellip; GREAT FITNESS FOAM ROLLER for back pain, sore muscles, pain relief and all kinds of muscle pain. Especially for bigger muscle groups of your body. ADDRESSES TRIGGER POINTS from a wide spread area, but also more concentrated areas because of the pattern of the grid. FOUR High Intensity vibration levels from 2,000RPM to 3,700RPM and a rhythmical pattern. NEWEST CORE STRUCTURE - built in a FAN to air out the temperature that motor creates to keep motor in a good environment when its working in such high frequency. RISK FREE ONE YEAR WARRANTY from the date you have purchased ActiveBall. We are proud to tell you the defect rate is below 1% and even if there is one, we are 100% guaranteed for a full refund or a replacement.