Made of high material for durability and stability Pressure can be adjusted by springs or air (nitrogen); Operation of the coil-over springs and air cylinder is helpful to reduce the shock No instruction included, professional installation recommended The suspension leg provides a smoother ride and better shock absorption management. The spring seat is insulated from the spring to ensure a quiet and comfortable ride The suspension shocks struts provides a smoother ride and better overall damping management Size:250MM Feature: Eye center to center : 220mm/250mm Spring Thickness 11mm Spring Diameter 67mm Mounting hole diameter: 10mm Mounting hole thickness: 25mm Rate(lbs/in) 1100lbs This product contains nitrogen and hydraulic oil. Please don’t rotate the inflatable screw. Contents : Package included: one pcs shock Note: This product is measured by hand and may have an error of 1-3cm, which is based on the actual product. If you have any questions, please feel free to e