The GLR-16 Buttstock for the AR15/M16 provides an enhanced versatility with it''s stock extension and adjustable cheek rest. Advantages are Non-Slip unique traction design rubber butt pad, allows fast and stable shoulder positioning. There are three integrated slots for sling attachment. The sealed storage compartment will hold two CR123 or AA batteries. The enhanced nonslip quality insures steady positioning on body armor. A unique patented anti rattle mechanism allows fit on commercial aftermarket tubes.