Ncstar's tri-rail receiver cover provides three rails for mounting an optic on top and accessories.The two side rails can be mounted in several positions for mounting flexibility, and are also removable.Four side set screws allow the receiver cover to be locked to the receiver for a secure fit.The see-through design allows you to still use iron sights when mounted.It is constructed of steel with an aluminum rail.Rails: BlackType: Tri-RailFirearm Type: RifleFirearm Model: See ThruMaterial: AluminumFinish: AluminumFeatures: Aluminum/SteelAdjustment Type: 1Positions: RifleLength Of Pull: Screw (4)Texture Type: No