Precision Reflex .308 AR10 SPR Delta Top Rail System 14in Flat Dark Earth. This rail ties the upper receiver to the forearm to create a very rigid shooting platform. This rail will also give you the SPR look in a 308 package. This rail will work with Armalite uppers. Specifications for Precision Reflex .308 AR10 SPR Delta Top Rail System: Manufacturer: Precision Reflex Color: Flat Dark Earth Fabric/Material: Aluminum Cant: 0 MOA Gun Make: AR Platform Package Contents: Precision Reflex .308 AR10 SPR Delta Top Rail System Precision Reflex 03-072-SPR-14A-DE: .308 AR10 SPR Delta Top Rail System 14in Flat Dark Earth