Manufaturer Part Number: SRDPISTON578X28Convert your srd45 suppressor to a.578x28 right hand thread pitch with the srd-piston-578x28.The piston is made of 17-4 heat treated stainless steel, with a matte glass bead finish, and it will fit a variety of hosts.Simply swap the conversion piston with the original piston in your suppressor to match your barrel thread pattern.Model: SRD PistonFinish: Black