After a fierce OP me help the two rollers to loosen the nerves in the trigger points on the body. The top coating presses gently unfairly increasing pressure on the nerves more points. Thus, everything can be well dimensioned in the medical treatment. The two variables I use in my back and legs. The material of the rolls is very high, and is easily dyed / will not peel off. From me so full 5 star satisfied.