We do not accept P. BOXES – PLEASE PROVIDE A PHYSICAL ADDRESS. We advise you to use a reputable carrier service when returning your goods. Please check the Voltage information and make sure it matches the one in your country. In case it’s not stated in the description, do ask us. We guarantee that your issue will be solved quickly. We usually respond within 24 hours on weekdays. Please Check the production date under seat of the chair. Please check the cylinder by opening the mechanism box under seat before purchasing: If the Cylinder has a cable pin hook on the top of the cylinder please reference to ASIN:B0B7QTP77K. If the Cylinder has a cable plastic actuator on the top of the cylinder please reference to ASIN: B0B7QL63KY or ASIN: B0B7QKNRX2. CLASS 4 LEVEL GAS LIFT CYLINDER — This heavy duty gas lift cylinder made with high construction industry standard (BIFMA Plus Qaulity) for Herman Miller Aeron Chair cylinder, ref code 1B65LR. ADJUSTABLE HEIGHT 6 INCH — Adjustable Height 6 Inch, the fully expanded height is 16 inch, the fully compressed height is 9.9 inch. DIAMETER — small black tube diameter: 1.1″ (28mm), middle chrome tube diameter 1.3″ (33mm), outside big black column diameter: 2 (50mm). REPLACEMENT PARTS FOR HERMAN MILLER AERON CHAIR — Please check the cylinder by opening the mechanism box under seat before purchasing. If the Cylinder has a cable pin hook on the top of the cylinder that this version will workable. If the Cylinder has a cable plastic actuator on the top of the cylinder that this version won’t workable, please reference to other ASIN: B0CCHQYDVG. MySit 6 Stroke Gas Lift Cylinder for Herman Miller Aeron Chair Replacement Duty.