Features Possess a good thermal fit to the piston and reduces the weight of the whole machine, thermal conductivity is increased by 42% compared with the bimetal structure Made after one piece forming, increase the strength of the machine body and improve the surface hardness, more durable Come with strong thermal diffusion ability thanks to adopt lightweight high silicon aluminum alloy The product has improved wear resistance, corrosion resistance and high temperature impact resistance greatly Possess surging power, strong gas compression ability, clear thread and smooth knob, not easy to jam, very smooth Specification:Item Type: Cylinder Piston Kit Material: High silicon aluminum alloy Cylinder Diameter: Approx. 52mm / 2in Package List:1 x Bearing1 x Cylinder1 x Piston1 x Piston Circle2 x Piston Ring1 x Piston Pin3 x Gasket1 x Spark Plug1 x Plastic Shell Package List 1 x Bearing 1 x Cylinder 1 x Piston 1 x Piston Circle 2 x Piston Ring 1 x Piston Pin 3 x Gasket 1 x Spark Plug 1 x Plastic Shell