Stern Defense 008SDRABADD1M Rapid Attach Buttstock Adapter Black Aluminum/Steel

To detach, push the button and twist counter-clockwise 30 degrees.The buttstock will then be separated from the firearm. To re-attach, align the two pieces, push in and turn clockwise 30 degrees. The steel locking mechanism automatically secures the adapter. It's 7075 aluminum construction and steel internals make the RAB-AD both robust and lightweight. The RAB-AD is designed for gas piston, direct impingement, direct blow back and radial delayed blowback systems in the AR platform.