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 th