I've been using those type of discs for years-to move heavy furniture without scratching floors or tearing carpets. That's what they were originally designed for. What a great idea for an exercise device.Now if only I'd seen the potential there.$$$$$$$$$$$$$ Missed the boat again! Not sure if it's fair to pick on the inversion boots as just a TV junk product,they were being highly touted by most health clubs back in the 80s/90s-'til it was discovered that for some people it wasn't a good idea to stay there long. Oh, the articles that were written,one would have thought that Ponce had finally found the Fountain of Youth.