The Midwest Industries Extended M-Lok Handguard fits the Sig 516. This lightweight, handguard features a rugged construction of 6061 aluminum, hard coat anodized for a lifetime of service. The M-LOK compatible design includes one five slot picatinny rail section and features five anti-rotation QD sockets for QD sling swivels. FeaturesInstalls on factory barrel nut, not included with handguardFeatures a monolithic type continuous top railFeatures five anti rotation QD sockets for push button swivelsLight weight with extremely solid lock upConstructed from 6061 aluminum hard coat anodizedExtends past the front sight tower for additional space for mounting accessoriesOverall length of top rail 7.25" width 1.840" height 2.17"Five slot M-LOK compatible rail piece included