The TI-RANT 45 Piston is an ASAP piston and features heat-treated stainless steel construction. They have a bead-blasted matte finish and are engraved to identify the thread diameter, pitch, and direction of rotation for installation. This model is to fit the TI-RANT 45 suppressor onto a 9mm, .40, or .45 caliber pistol with an M16X1 LH tpi thread pattern.