The GP9 is a 9mm suppressor intended for self-loading pistols up to 9mm caliber. Contains a “Nielsen device” to ensure reliable function in a semi-auto pistol. Utilizes a combination of steel and aluminum for durability and weight-savings. A monocore construction makes it user-serviceable. The GP9 is available in either 1/2×28 or 13.5x1LH thread options.