UNIVERSAL SIZE GAS LIFT: Our office chair cylinder replacement will fit just about any office chair including popular brands such as Herman Miller, Hon and Amazon Basics! If for some odd reason it doesnt fit your specific office chair, return it for a no questions asked refund and we will even pay for the return shipping. You have nothing to lose! SUPER HEAVY DUTY CLASS 4 CYLINDER! Our pneumatic piston replacement cylinder is class OEM standard hydraulic pistons are often lower class pistons, which is why they fail and start sinking so often! If you want an office chair that wont sink after a few months look no further. Our cylinder for office chairs can even safely support up to 1000 lbs!