Razer Iskur Gaming Chair Gas Cylinder

I have a Razer Iskur chair that has been great for me but it is now out of warranty. Throughout the day it slowly slides down so the Class 4 cylinder needs to be replaced.  I need to know what are the diameters of the original gas cylinder that comes with the chair. I don’t want to start buying class 4 cylinders across the board hoping it is the right one or works out. Thank you in advance!