1)Gas Spring Plastic Piston,plunger 2)ISO9001:2000 3)Outside Diameter: 20x8, 16x6, 13x5 Gas spring plastic pistonISO9001:2000Outside Diameter: ¢20×8, ¢16×6, ¢13×5Material: nylon66Many types are available for gas spring, damper and shock absorber.OTHER: Gas Spring Plastic Piston,plunger