This detachable magazine is constructed of steel with a black oxide finish and is compatible with your Ruger Security9. This model has a 15-round capacity. Specifications and Features: Caliber: 9mm Luger Capacity: 15 Finish: Black Oxide Model: Security-9 Material: Steel Type: Detachable Model Fit: Ruger Security-9 Brand Fit: Ruger Capacity: 15