I got a short length one from ****'s sporting goods. I got a longer one from the physical therapy I go to. I suggest the longer one because you can get your whole body on it. They are about 5" in diameter. It does help with stretch. I had surgery on left side, which still acts up. Tight muscles in neck and shoulder area. The right needs surgery, which I have both nerve and arterial compression but was not as bad as left side. I want to put off surgery as long as possible, but not sure how long that will be. Good Luck