Rugged Suppressor OEM Internal Shoulder Piston Copper 1/2"-28 tpi Rugged Suppressors Piston uses 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. This Model Is For Use With for Glock 43 And Sig P938. Model: OEM Material: 17-4 Stainless Steel Thread Pattern: 1/2"-28 tpi Finish: Copper