LiVond hot/cold massage roller massage ball is amazing~ It works wonder on our aching muscles! Works great on tennis elbow, aching shoulders, lower back muscles, legs, feet... It helps relieve muscle aches, and soreness with simple roller functions. It's super easy to use this massage ball on the go or at home. We just love it so much~ This roller massage ball can be used hot or cold simply by placing the gel-filled ball in warm or cold water for couple of hours. Stainless steel ball can be removed from the cradle. Very easy to operate ~ A must have if you are having muscle pains~ Great quality ~