NOT STANDARD DIMENSION - (8.6 inch x 6 inch wide) with 1.1inch hole diameter and 2.5 mm tickness - mechanism features. Turn the steering wheel to tighten or loosen (adjust) the forward backward tension and move the arm for height. Fit for the majority of gas cylinders. It is VERY IMPORTANT IMPORTANT IMPORTANT to measure your mounting hole dimensions ordering. NOT STANDARD SIZE check with . OFFICE CHAIR MECHANISM REPLACEMENT LETS YOU YOUR OLD CHAIR AND SAVE MONEY- Is your favorite office chair in bad shape? your own basic office chair replacement and make your chair new again quickly and effortlessly.If you're unsure about the gas cylinder, you can also replace it with a 5-6 inch gas cylinder. Measure your old piece first, other sizes are available, to avoid an unnecessary return. EASY DISASSEMBLY AND ASSEMBLY- We have clear step-by-step photo instructions on listing page, so even a non-professional can install this mechanism chair.You everything you need with the purchase so replacement is hassle free. It is much more environmentally friendly, economical and pleasure to repair your favorite office or gaming chair. SUPERIOR QUALITY REPLACEMENT MECHANISM ORDERS- a new mechanism that fits most gaming chairs, executive chairs and office swivel chairs. It is very important to measure the dimensions of your mounting hole ordering. This heavy duty control mechanism withstands a heavy weight of 450 lbs. Enjoy , quiet rotation on your office swivel chair. Also fits gas cylinder and many others. Colour: black Material: metal Package Contents: 1 x office chair Only the above package content, other are not included. Note: Light and different displays may cause the color of the item in the a little different from the real thing. The measurement allowed error is +/- 1-3cm.