Well... I'm mixed about this chair.I originally wanted something from the Office Master line like the BC44 or BC48 because I've had great success with them at work. But shipping to my location was going to cost more than the chair. And this one was out there with decent reviews.Overall, the chair seems pretty well built. But... The jury is still out on how I'm going to react to this "firm" foam. I don't know that it's really going to help with my lower back issues compared to how well the Office Master chairs seem to have worked. The "dillon" material seems like a pretty good fake leather and is comparable to that on movie theater seats though. (I've had an Office Star chair in the past where the fake leather stuff started peeling, so I'm cautious.)For what it's worth, the instructions with this chair call it the "pro line II" but that's not included in the Amazon listing.My big issues with this chair are:(1) The include allen wrench did NOT work for all the screws. No way. Fortunately I had a separate kit with hex wrenches that could handle a couple of the weird angles with the under-seat mechanism. NO way the included wrench would have worked for everything. Be ready to buy a separate kit to properly assemble this.(2) Instructions. The seat pieces for the arm rests weren't even mentioned in the instructions; it looks like they were expected to be pre-installed. And other steps were off. For example, the instructions referred to two screws too few to install the seat mechanism, but the "extra" screws themselves were actually included. I'm not happy when I drive myself crazy with assembly instructions and finally really do have to just toss them because they're off.(3) Customer service. After getting everything else assembled, the final step of attaching the seat back to the base hit a standstill. The final included screw didn't stay in place, and I couldn't even tell from the instructions how it was supposed to. No good at all if you have a seat back that's going to fail on you. After getting zero response from Office Star customer service, I went to Home Depot to find the closest screw set that would fit and hold things in place. But there was nothing that would work with the thicker included screw. So I now have a sort of functional chair, but I'm constantly worried about when the back is going to fail with the pieces I had to toss in there, and I'm going to be injured. And there's no way I can realistically take everything apart and pack it up again to ship back to Amazon for a refund.So... I'm ultimately super disappointed that this chair with a supposed three year warranty cannot even get a response from customer service when they didn't include the right parts. I'm just waiting to be injured by this thing. And for $250+, I'd expect assembly instructions that better match, customer service that at least responds, etc.If this whole thing could be properly assembled with decent instructions and the right parts included, it probably would get 4 stars. But... wrong tools, wrong parts, and no response from Office Star customer service, and this thing gets dinged big time. Two stars, and if I could do it over again, I would. Once this is shipped to you, for the most part you're stuck. And the "warranty" and "customer service" look to be worthless. Be ready to do some hardware store shopping to get this thing assembled, and hopefully it doesn't collapse on you with what you find to get it put together.