Blued steel, 17-Round, 9x19mm caliber magazine. It is compatible with the PC Carbine and PC Charger with the SR9/S9 magazine well insert installed. It is not compatible with the Security-9 pistol. This magazine may be used on the SR9c. It is highly recommended that the magazine adapter (item 90341) is used to ensure that the magazine is properly aligned in the handle of the gun. Genuine Ruger Factory Accessory.