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Looks a bit like a gas chair lift cylinder - https://www.amazon.com/Cylinder-Office-Replacement-Universal-Hydraulic-Pneumatic/dp/B097HJRVDG
That is useful to know. I just replaced the gas shock for $25. Very difficult to get the old one out as it is a friction press-fit. Required a modern pipe wrench, a LOT of torque, and a hammer to pound out the bottom piece from the base.
fire and lots of it .....jk you could call the company up and see if they will ship replacement for free or cheap. or u could get a new chair base but some times its a pain in the ass to take off from old one. soooo u could just remove the gas spring off and replace it with the chair base as well if it proves to be a pain in the ass. as always make sure it works and is returnable if it doesn't.