Don't Know What Gas Cylinder I Need- Universal Chair Gas Lift Cylinder Pneumatic Shock If you don't know what chair you have or it's a no-name brand chair, chances are our universal chair shock will work on it If you bought your chair at an office supply superstore, it's very likely this universal gas cartridge replacement will work. This gas lift can be used with or without the black column- Shaft has a 1" diameter. Hydraulic is 2" in diameter, black part is approximately 9" long Full refund available on item- 2 year Warranty included