Features 1、Made of lightweight high‑silicon aluminum alloy, come with strong thermal diffusion ability 2、Compared with the bimetal structure, the thermal conductivity is increased by 42%, and has a good thermal fit to the piston and reduces the weight of the whole machine 3、One-piece forming, increase the strength of the machine body and improve the surface hardness 4、Greatly improved wear resistance, corrosion resistance and high temperature impact resistance 5、Strong gas compression ability, providing surging power, clear thread and smooth knob, not easy to jam Specification Item Type: Cylinder Piston Kit Material: High silicon aluminum alloy Cylinder Diameter: Approx. 38mm / 1.5in Package List 1 x Cylinder 1 x Piston 2 x Piston Circle 2 x Piston Ring 1 x Piston Pin