JMac Customs 4C 1/2-28 Slim 9mm 4-Port Muzzle Brake Black Nitride Black RRD-4C-28-S-9. This RRD-4C-S was designed specifically with the NAK-9 pistol in mind. Unlike our other 1/2-28 threaded RRD-4C devices this device will install on your NAK-9 (or...