Genuine Sig Sauer factory replacement threaded barrels for drop in fit. Threading allows for use of suppressors or other muzzle devices. Thread pitch for 9mm is 13.5 X 1mm LH, and .45ACP is .578 X 28 TPI. Mfg: Sig Sauer, Inc. SPECS: Thread pitch for 9mm is 13.5 X 1mm LH, and .45ACP is .578 X 28 TPI.
