I first used the gymnic stability ball plus at the gym in my building and I loved it. A few days ago I received the one I ordered, size 65cm. I am 5'.7''1) delivery- estimated time up to 4 days- i received it in two days2) i inflated the ball, almost firm- because in the first day it streaches a little bit, i had to inflate it two more times( i also called customer service=Perform Better to ask if it was normal that the ball got softer,they told me that it was ok). Third day, everything was back to normal. I am very happy with it. and the CD-rom shows all the great exercises.If you want to purchase a Stability ball purchase this one by Perform better,best quality

This is a good exercise ball, pretty much everything it's supposed to be. It's supposed to be extra tough, and so far that has been true. Although I ordered the 55cm size because that is supposed to be correct for my height, it still seems a bit small.

This stability ball is by far one of the best in quality. What you can purchase at Sports Authority or Modell's or Dick's is not nearly the same quality or price. You pay for what you get. This is a good buy.

The Gymnic stability ball is a great product and very long lasting. I was so impressed with the quality, I ordered one for a friend and a replacement one for myself (my grandchildren decided to put pins in my last one).