This Apex 9mm Threaded Barrel is designed for the M&P M2.0 Compact model with a 4.00" factory barrel. The stainless steel barrel has a black Melonite finish and features a 1:10 twist rate that is designed to increase accuracy performance. The thread pattern is 1/2-28 and a thread protector is included. This barrel is a true drop-in and requires no fitting.