A3 Tactical Modular Folding Stock 2-Bolt Hinge Mount 6.25In Offset Ext Arm Polymer Butt-Plate w/Magpul v2 Rubber Butt-Pad Black MS-H1-6.25-OFF-BP4. They easily mount via 2 screws to the rear of adapters. NOTE: the adapter is not included with the stock...