The Rugged Suppressors series of Pistons utilize a non-slotted design creating a full circumference gas seal. This drastically lowers gas blowback for a more enjoyable shooting experience. Machined from 17-4 Stainless Steel and heat treated this piston is built to last. Available Thread Pitch Options:1/2x28.578x281/2x369/16x24M13.5x1 LHM14.5x1 LHM16x1 LHM16x1 RH1/2x28 Internal Shoulder Rugged Suppressors 1/2x28 Internal Shoulder Piston OP009