A3 Tactical Modular Folding Stock 2-Bolt Hinge Mount 8.25In Offset Ext Arm Polymer Butt-Plate w/Magpul v1 Rubber Butt-Pad Black MS-H1-8.25-OFF-BP3. They easily mount via 2 screws to the rear of adapters. NOTE: the adapter is not included with the stock...