Agency Arms 118 Single Port Smith & Wesson M&P9 1.0 Barrel Compensators Black 118S-M1-BLK. 0/M2.0. It features a 1 chamber design (1 vertical port) and is designed to work with the M&P9/M&P9 (4in 4.25in & 5in) platform. It is machined from 7075...