1. Pressure can be adjusted by springs and air (nitrogen). 2. High quality,high-performance motorcycle parts. 3. The damper and spring designed for long durability. 4. Reduce bumps in the driving of motorcycles. 5. Easy to install. Note:we will send by two parcel,when you make order, it mean that you agree with 2 pacakges.thank you very much. 1 Pair Motorcycle Air Shock Absorber 360mm 14″ Rear Suspension Spring Scooter Pit Dirt Bike Gokart Quad ATV Item:1 Pair 360mm Rear Air Shock Absorbers Color:Gold + Black Material: Aluminum+Iron Total Length: 390mm Eye Core Length: 360mm Eye Diameter: 12mm Eye Thickness: 20mm Spring Thickness: 7mm Spring Width: 60mm WorStroke: 60mm Factory Air Pressure: 0.4 Mpa Maximum Air Pressure: 0.5 Mpa Air Reservoir: Adjustable Placement On Vehicle: Rear,Left, Right Fitment: Universal Motorcycle Eye To Eye Length 360mm. Features: Note: 1.We provide clear pictures, measurements where possible. Please check as much as possible to make sure the item is the one that you need. 2. Please allow 0.5-1 inch difference due to manual measurement. (1inch=2.54cm) 3.The color of the actual items may slightly different from the listing images due to different computer screen, thanks for your understanding. 4.There are no instructions included in this kit.If you want to know how to use or install it,please contact us by Email.We will provide help as much as possible. Package Includes: 2 x Shock Absorbers 2 x Adjust Spring Tools