Piston and Rings: Low expansion aluminum alloy piston with international standard piston rings for positive sealing are elevated temperatures. Crank Case and End covers: High quality graded cast iron. Cylinder: Special cast iron, deep finned for quick heat dissipation. Finger Valves and Disc Valves: Special hardened, ground lapped stainless steel for longer durability & less wear and tear. Air Receivers: All Air receivers are hydro-pressure tested and all compressors are tested for specified cycles in final assembled condition. Fan Agro dynamically designed fan with large blades for higher air flow.