The GLR-16 Buttstock for your AR15/M4 provides you with enhanced versatility with it's stock extension and uniquely designed rubber butt pad for fast and stable shoulder positioning. Its unique patented "Anti-Rattle" mechanism, fits perfectly on MIL-SPEC and commercial after-market buffer tubes. Made from fiberglass reinforced polymer composite, the stock features three integrated slots for sling attachment, one in the front and two at the rear and water-resistant anti rattle storage compartment for two CR123 or AA batteries. This model has a black finish and an adjustable cheek-rest.