A3 Industries Rear Stock Adapter for M11/9 6061 T6 Aluminum Picatinny Black. Machined from aluminum with a steel mounting insert these can be installed in minutes. Fits Open-bolt M-11 only. Specifications for A3 Industries Rear Stock Adapter for M11/9: Manufacturer: A3 Industries Color: Black Gun Make: Cobray Gun Model: Universal Gun Type: Carbine Fabric/Material: 6061-T6 Aluminum Additional Features: Picatinny Finish: Type II Low Gloss Anodized Features of A3 Industries Rear Stock Adapter for M11/9 Open-bolt M11 only Easy 5-minute installation Package Contents: A3 Industries Rear Stock Adapter for M11/9 What firearm models does the manufacturer say A3 Industries Rear Stock Adapter for M11/9 is compatible with? The manufacturer says that A3 Industries Rear Stock Adapter for M11/9 is compatible with UniversalA3 Industries RSA020: Rear Stock Adapter for M11/9 6061 T6 Aluminum Picatinny Black