The AD M4 Folding Stock Adapter is designed to be compatible with a wide range of AR-15 and AR-10 rifle set ups. Whether you run a direct impingement or piston gun, this AR folding stock adapter will work. This high-grade billet machined aluminum constructed product allows you to build a compact rifle customized to your storage or transportation needs. No need for a proprietary bolt carrier group or buffer tube, just install on your receiver and you are ready to go. A single button allows you to quickly fold your stock for storage or unfold it for shooting. This Folding Stock Adapter is a great option for those looking to build an AR that won’t take up much space in the range bag.