Quantity: 1 piece. Material: Steel Color: Black Long Mounting hole center distance: 210mm/8.3inch Wide Mounting hole center distance: 130mm/5.1inch Total Length: 238mm/9.4inch Total Width: 155mm/6.1inch Thickness: 2mm/0.08inch Feature: Solid and sturdy, heavy duty, durable for long-time use. The office chair tilt base can control the height of the seat to prevent repeated sinking.. Twist hand wheel to tighten or loosen (adjust) backward tilt tension. Application: Features with universal size in 28mm/1.1inch diameter, the tilt control mechanism fits all height adjusting cylinder chairs, which is suitable for replacing and repairing the original swivel chair. Note: All dimensions are measured manually and there may be small deviations. If you encounter issues with any product, please do not hesitate to contact us, we will be happy to help you solve it.