I had one back in '11 for the same problem and this was a totally different experience. First one they stuck me headfirst in a little tube that I bare fit in and I'm on the slender side and then spent 30 minutes destroying metal trash cans with sledge hammers or so it sounded. This one was lots larger, roomy in fact, with cool air blowing thru it and I got to go in feet first. Someone with very little talent spent quite a while trying to play a synthesizer very loudly and then someone spent several more minutes working on a bolt with an impact wrench. It mush have been a big one as I could feel the machine vibrate and I got a back massage from it. It only took 20 minutes for this one. I sure was glad for the earmuffs the tech stuck on me. Hooray for advancements in medical science.