A3 Industries Rear Stock Adapter for HK MP5/SP5 Polymer Picatinny Black. Completely unique in design this adapter provides improved stability by covering more surface area of the receiver. We also include a 1/2in thick high-density polyurethane buffer. The A3 Industries adapter allows the use of our complete line of modular stocks and braces and can also be configured with our Picatinny rail. The Picatinny rail will allow you to adapt any side folding stock (or arm brace) designed for use with Picatinny style mounts. The bolt pattern and locating lug on the rear of the adapter provides a positive modular mounting platform for a wide variety of currently available stocks/braces. Specifications for A3 Industries Rear Stock Adapter for HK MP5/SP5: Manufacturer: A3 Industries Condition: New Color: Black Gun Make: Heckler & Koch Gun Model: Heckler & Koch SP5 Heckler & Koch MP5 Gun Type: Submachine Gun (SMG) Fabric/Material: Polymer Additional Features: Picatinny Features of A3 Industries Rear Stock Adapter for HK MP5/SP5 Polymer/Aluminum hybrid design OE-fit to receiver with reinforced recoil spring seat 1/2in high-density polyurethane buffer included No modifications to firearm needed Modular design for various cross-platform use Large #10 threads and positive lug for increased mount stability Package Contents: A3 Industries Rear Stock Adapter for HK MP5/SP5 What firearm models does the manufacturer say A3 Industries Rear Stock Adapter for HK MP5/SP5 is compatible with? The manufacturer says that A3 Industries Rear Stock Adapter for HK MP5/SP5 is compatible with Heckler & Koch MP5 Heckler & Koch SP5A3 Industries RSA015: Rear Stock Adapter for HK MP5/SP5 Polymer Picatinny Black