The other day I bought a kneeling chair to help my posture. I went to the Healthy Back store and bought an inexpensive one; I liked it better than the others ones. I ended up getting the Healthy Back Kneeling Chair. It wasn’t until today that I discovered a huge design flaw in the chair. I was noticing that the chair wasn’t rolling properly and after some detective work (and luck), I found that if I lowered the chair, the problem went away. The chair is in two pieces in an x pattern with a height adjustment (and a pivot bolt) connecting them. The problem is that all 4 casters are perpendicular only at the lowest seat position. As you raise the seat, the front part pivots causing the casters to no longer be rest flat on the floor. This is fine on carpet as the carpet and pad take up the slack, but I have hardwood and the chair doesn’t roll. I went back to the store and after a brief explanation and demonstration, they let me exchange it. I got the chair I was originally going to get and because of their special sale, it only cost me $1.08 more; I still like the other chair I got because of the angle adjustment, but I’d rather not scratch my floor when it doesn’t roll. I was very pleased that the store made things right.