So now I do not know what I would have done without this part. Had total problems so back to the rear chunk. Ouch. Too much Schreibtischsitzerei is stupid (I know myself), thus everything was totally tensioned. Did it then at a friend saw who uses it for her disabled daughter and gave it a try there. If I had not felt it myself, I would never have believed that such a device has such a power. It's pretty hard, and I edit my problem areas always lying down so it slips' on me through the long handle, all by itself. That's pretty comfortable and incredibly effective. There is a knock or vibrate in different thicknesses, with or without a red light. However, I prefer the red light. Each side handle about 10 minutes and the pain subsides immediately after. The orthopedist seeth me no more, because I feel really bad tension or adhesions (have fibromyalgia) have now got super grip. If I had not tried it myself, I would never have believed that such a part can really work. Have now brought for my daughter who treated her regular contributor to tense neck so. Am thrilled and grateful that there is such a great thing.