The cylinder has a 1-1/8" (28mm) diameter piston shaft and a 2" (50mm) diameter column. Are you tired of sitting down in your office chair only to find out that the cylinder no longer lifts up and down? You have three options: Deal with the sinking chair, buy a brand new chair, or replace the broken cylinder with a new one. Replacing the chair's gas lift cylinder can be a great option and save you money...IF you replace the cylinder with one of high quality, you have the tools to remove the old one, and you know how to install it. The Office Oasis is here to provide the best solution for your sinking office chair. When you purchase one of our chair cylinders, we'll send you: *The highest quality gas lift cylinder in the industry. * Our easy to use, chair cylinder removal tool. * Step-by-step instructional e-book illustration how to remove and install a chair cylinder. * Pair of gloves to help with the installation. * Amazing customer service. Our chair cylinders are the universal industry standard size and fit most office chairs. But if for some reason it doesn't fit your specific chair, return it hassle-free and no questions asked. In addition, each cylinder is backed by our lifetime manufacturer's warranty.