Features The thermal conductivity is increased by 42%, and has a good thermal fit to the piston and reduces the weight of the whole machine Greatly improved wear resistance, corrosion resistance and high temperature impact resistance, safer and more stable Lightweight high‑silicon aluminum alloy possess strong thermal diffusion ability One‑piece forming works for increasing the strength of the machine body and improving the surface hardness Strong gas compression ability, surging power, clear thread and smooth knob, not easy to jam, very practical Specification: Item Type: Cylinder Kit Material: High silicon aluminum alloy Cylinder Diameter: Approx. 48mm / 1.9in Package List:1 x Cylinder1 x Piston2 x Piston Circle2 x Piston Ring1 x Piston Pin2 x Fastening Screw1 x Spark Plug1 x Bearing1 x Rubber Sleeve Package List 1 x Cylinder 1 x Piston 2 x Piston Circle 2 x Piston Ring 1 x Piston Pin 2 x Fastening Screw 1 x Spark Plug 1 x Bearing 1 x Rubber Sleeve