Great bar stool, part of a set of 4 stools and table. Fast delivery. Some assemble required. Stool back rest attaches to seat frame with 8 machine screws. This is the hardest part of the assemble. Best to assemble all screws and washers (locking and flat) before installing. Install all screws loosely and then tighten.   Out of 4 stools I had 2 screws that cross threaded and had to replace one at the store. The rest is pretty straight forward. Decide how you want the weave of the material on the cushion and install all of them the same for best look. The screws go into the seat bottom very easily so it must be particle board. I don't think that will be a problem, just don't over tighten. Seats are firm and a bit stiff to rotate but overall I am very satisfied with the set.