Mastery Mart 15" To 22" (8" Stroke) Long Adjustable Gas Lift, Matte Black Product Features ??Adjustable Height 7.6 inches?The minimum height of the fully chair piston is: 15.2 inches (38.5cm), the fully expanded height is: 22.4 inches (57cm) and it has an adjustable height of 7.6 inches, which allows you to rise higher. (Note: measured before purchase) ??Universal Fit Size for Most Chairs?The outer cylinder diameter connected to the base is 2 inches (5 cm), and the inner cylinder diameter of the gas lift connected to the chair is 1.1 inches (2.8 cm). This pneumatic piston cylinder will fit almost every office chair on the market including herman miller aeron. Please confirm these measurements before making a purchase. ??Upgraded Class 4 Gas Cylinder?Mastery Mart's office chair cylinder replacement is made of premium steel. This heavy-duty gas lift cylinder is manufactured to meet the highest industry standard (BIFMA/ANSI), the lift has a maximum capacity of up to 450 LBs/ 204KGs. ??Eliminate Sinking Concerns?Prevent sinking issues by removing the old cylinder using a hammer or wrench. Simply assemble our new cylinder into the base and attach the seat. Our office chair lift provides seamless 360-degree rotation. ??100% Satisfaction Guaranteed?For any issues with using our chair shock replacement, please don't hesitate to contact us. We are here to provide guidance, offer replacements, or process refunds, depending on your specific case. Your satisfaction is our priority. Shipping: Shipping is complimentary within the lower 48 US States. We Do Not Ship to PO/APO Boxes, HI or Alaska We Do Not Ship Outside of the Continental US All items ship within 24-72 hours of Payment For large items that require Freight shipping a valid phone number is required to call and schedule your delivery Terms of Sale and Feedback: Feedback is extremely important to us and If you are satisfied with our transaction, please take a moment to leave Positive Feedback. YOUR Satisfaction is our #1 Priority! If there are any issues, PLEASE contact us BEFORE leaving a neutral or negative rating so that we may resolve any concerns. We PROMISE we can make you happy if you give us a fair chance. Returns / Concerns: All items qualify for returns within 14 - 30 days of receipt. Buyer is responsible for return shipping on any item that is not damaged Please be sure this is an item you want before making your purchase. Customer Satisfaction is our TOP priority! All items are IN STOCK at time of listing. Inventory changes constantly and it is impossible to maintain a perfectly accurate count of all items. Please do not penalize us if we have to issue you a refund! Thank You For Your Business!