The Battlelink Utility Lightweight Collapsible stock is a slide on replacement for the standard M4 AR-15 buttstock. Featuring a large rear storage compartment that is water-tight, a customizable foam block minimizes noise and keeps items in the storage compartment secure. Two quick-detach sling mounts are positioned on the front and rear of the stock body for sling attachment. The shape of the upper stock provides an improved cheek weld over the conventional M4 buttstock. Accessory mounting provisions are built into the stock body that accepts Garmin GPS or cheek risers. This is a stock assembly, and includes a commercial extension tube, lock ring, end plate, spring and buffer.