Made 100% in Italy, the FPS Softair PM04 ZERO-SHOCK piston utilizes an elastomer-infused technopolymer body paired with FPS’s patented shock-absorbing design to cushion mechanical stress transferred from the tooth rack to the piston body. Features a full rack of MIM (Metal Injection Molding) SAE 4650 heat-treated steel teeth (HRC38-42) with a pre-removed 2nd tooth and lowered 3rd tooth to optimize Angle of Engagement (AOE) out of the box for high-RPS builds. Includes anti-friction sliding guides with integrated grease retention grooves and a decentralized rack seat for smooth gear engagement. Fully compatible with standard Tokyo Marui-spec Version 2 and Version 3 gearboxes.