Strike Industries FSADUALSTOCK: The Strike Dual Folding Adapter is a versatile dual folding stock adapter that folds to either the left or right side of the weapon platform. It mounts to a 1913 Picatinny interface with built-in locking lugs for secure attachment. The included Stock end is a great ergonomic option for completing a build. The Dual FSA's name comes from its ability to fold to the left and to the right, as well as its interchangeability to swap out the Stabilizer end to a Stock end. Use it with most 1913 Picatinny rear ends, including the Strike AR Picatinny Stock Adapter, or any factory OEM weapon with a Picatinny rail.