I work approximately 10+ hours from home from Monday to Sunday depending on how crazy work gets. I needed a reliable chair and that is when I ran into ergonomic chairs and found the SIHOO M18 ergonomic chair after a crazy amount of days and hours or searching and reading reviews. Once I received the product and assembled it, I knew it was a good quality chair. It takes around 30-45 minutes to assemble with the tools provided with the product. It has great head rest, lumbar, sitting support. Bought it on October 2023 and provided everything I needed. About a week ago or so, I started noticing the tilt adjustment knob was getting stuck and not actually doing anything to the tilting tension. The back rest became wobbly. It was becoming a problem because I suffer from chronic neck and back pain and was the reason I had bought this product. Forgot to mention that it helped relieve my back and neck pain. I tried tightening the screws, disassembling and assembling the chair again, but nothing worked. My pain was getting worse and was affecting my work so I contacted the companies support group via email through amazon. I explained basically everything that I explained in this review and they requested some videos and pictures to see if they could find a solution. Those pictures and videos were sent. They replied and stated they would send me a new head rest, head rest mount, and new mechanism. I appreciated their quick reply and solution but I wanted to upgrade because I didnt want to experience the same pain again so I told them if I could get a discount to another SIHOO model, product models provided in email, for the same price amount of the replacement parts they were going to send me. They agreed after speaking to their supervisor!!!!! For me it was a surprise! I expected them to not care and just send me the parts they had mentioned. For the first time in my life, a company actually listened to its customer and found a solution that the customer needed! Plus, this was all solved from January 8 to January 12, 20205! They respond in such a quick manner, respectful, and professional! The products have a lifetime warranty and the company actually means it! I recommend the SIHOO M18 ergonomic chair for someone that wants to game comfortably or works in an office or from home at least 6-8hours a day. It is comfortable, sturdy, well made, tilting mechanism, comfortable sitting cushion, comfortable arm rest, great lumbar support, and AMAZING CUSTOMER SUPPORT!!