Bests & Worsts Reviews from Amazon

For all the 1-star reviews saying that the ball is too small...please read the directions about how to properly inflate the ball. It needs to be done in two sessions, to allow the ball to stretch to its full size. First, inflate it as far as it will comfortably go. Put the plug in. Wait a day or two. Then add more air and it will easily achieve 52cm. I effortlessly got mine too large and had to let out some air. The ball does gradually lose air over time, so it needs to be "topped off" every few months or so if using it often. The downside to this ball chair, in my household, is that the ball is NOT cat-proof. On a whim, my 18-lb cat decided to mount the ball. We heard a pop! and then a slow swishing sound. Now we just have a sad, crumpled, wad of rubber laying in the base of the chair frame. Needless to say, I'm here to purchase a replacement ball.