Sniper® Low-profile Quad Rail Gas Block for AR-15.
Replaces your A2 front sights and provides 4 Picatinny rails for accessories. Fits 0.75" regular barrel and standard gas tube. Precision machined to tight tolerances from aircraft aluminum, with a hard anodized Matte Black finish. Simple installation, no gunsmithing required. Top rail is lower than flat top by 0.28". Includes gas tube roll pin and locking screws.