Norsso N320 Compact/Carry BBK Compensator, 9mm - BLACKNorsso BBK Compensator Features: Machined from solid 7075 Aluminum billet in our Las Vegas, NV facility Two compensator ports for vertical and angular gas control Tapered lower geometry to seamlessly integrate with full size length frames and compact length slides Compatible for 9mm applications Attaches to 1 2 28 Right hand threaded barrels Note: Includes two set screws for mounting; 2mm hex head driver is required. Recommended torque per screw is 22