The Strike AR Picatinny Stock Adapter gives the user the ability to mount a 1913 Picatinny interface stock/stabilizer assembly where normally the receiver extension is attached. For ARs that do not need an in-line buffer and buffer spring to function, this is a simple, fast and budget friendly conversion that works on both AR-15 and AR-10 lower receivers. The Strike AR Picatinny Stock Adapter mechanism threads into a standard AR rear 1 3/16"-16 HSS right hand thread and has an anti-loosening detent that is very positive and tactile while keeping the rear detent spring captured for the rear takedown pin. The 1913 Picatinny section of this adapter includes a 4-slot rail section. As an Mfg: Strike Industries