Features Easy to Install: Fit for Stihl MS660 chainsaw, chain saw accessory is easy to install and easy to replace. Compact Structure: With good wear resistance and long life, chain saw accessory is compact structure and high hardness. Package Includes: High quality chainsaw cylinder piston assembly and complete accessories. Piston Diameter: The piston diameter is 54mm/2.1in, the chainsaw cylinder piston kit is precise part cast from special material. Stable Performance: With stable performance, the damaged or broken one can be easily replaced. Specification: Item Type: Chain Saw Accessory Cylinder Material: Die-Cast Aluminum Piston Material: Aluminum Cylindrical Pin Material: Alloy Steel Piston Ring Material: Ductile Iron Circlip Material: 65Mn Cylinder Coating: Chrome Plating Fitment: Fit for Stihl MS660 Cylinder Assembly Piston Diameter: Approx.54mm/2.1in Weight: Approx.900g/31.7oz Package List: 1 x Cylinder1 x Piston1 x Cylindrical Pin2 x Piston Ring2 x Circlip  Note: 1. Please allow 1-2cm error due to manual measurement. Thanks for your understanding. 2. Monitors are not calibrated same, item color displayed in photos may be showing slightly different from the real object. Please take      the real one as standard. Package List 1 x Cylinder 1 x Piston 1 x Cylindrical Pin 2 x Piston Ring 2 x Circlip