Chair has a glitch. When you attach the seat to the roller base the connection is not good. In order to keep the seat from separating from the base you have to jam it in and lock the up/down lift arm. If you recline the chair at all the seat pops out of the base and you fall to the floor. We purchased this chair once before and when the chair broke we didn't know this was the case. I put the chair together this time and that's how I discovered the glitch in this product.
I actually purchased the Vartan first but returned it because it was so uncomfortable. The Vortex was more comfortable to me. Unfortunately less than six months after I bought it the back completely broke off putting me on the floor. The chair is rated for 275 lbs and I'm well under that.