The massager is good, has already tried. It is important to perform everything according to the instructions. Watch the posture. There are three springs in the set. I took medium, green, because I'm engaged in other UPR. And I know my load. Everything works. The seller put as a gift a silicone thick sticker-neck puller. Thank you very much. The seller is perfect, I recommend to buy, if engaged regularly, should help, tighten the neck and chin.