I received this last week and put it together today. One prethreaded hole on the bottom of the seat and another on the back did not work as expected with the provided screws. The hex wrench has been completely stripped trying to get these two screws into the chair. I had another of the correct size and used that in addition. I am still unable to get the screw fully into the seat. I was finally able to get the back secured properly.

Also, the lever for height adjustment interferes with the piston that controls the height, so every time I sit down, lean back, or shift in the chair, they make noise.

I will be returning this, assuming I am able to disassemble with the faulty screws.