Features: 1.Wide Application: Shock Absorber has a wide range of applications and is suitable for most 50cc to 150cc 139QMB 157QMJ Scooter Moped Pocket Bike Mini Dirt Bike with a Single Rear Shock. 2.Adjustable Springs: Suspension shock absorber with 5 levels of adjustable damping, you can adjust the strength that best suits your needs to cope with different road conditions. 3.Stable Performance: Manufactured from high class materials and high performance springs, the overall stability and durability of the shock absorber are effectively guaranteed. 4.Superior Material: suspension shock damper is made of premium materials, which is hardness, not easy to deform, sturdy and durable and has a long service life. 5.Ideal Replacement: The suspension shock damper has a 300mm core distance and is a universal replacement for the 300mm core distance single hole damper. Specification: Item Type: Shock Absorber Material: Steel alloy + high performance spring + rubber Features: With 5 levels of adjustable damping, you can adjust according to your load (Please note that you must use the adjustment tool, otherwise it is easy to cause finger loss) Mounting Hole Distance: Approx. 300mm/12in Total Length of Shock Absorber: Approx. 330mm/13in Inner Diameter of Hole Center: Approx. 10mm/0.4in Spring Diameter: Approx. 7mm/0.3in Mounting Hole Thickness: Approx. 21mm/0.83in Application: For the replacement of the original shock absorber, renovation, upgrade, modification, decoration, etc. The new shock absorber provides a smoother ride and better overall damping management to improve ride comfort Fitment: For most 50cc-150cc 139QMB 157QMJ Scooter Moped Pocket Bike Mini Dirt Bike with a Single Rear Shock Note: Please check the size carefully before purchasing to ensure compatibility