Front sight mounted rails securely attach to AR15 style front sights.Two rails for laser, light and other mounting applicationsAvailable in aluminum (FSM15X) or polymer (FSM15P) modelsAluminum model accepts Forward Barrel Rail (FR1) creating a three rail front sight system (XF3)Part #: FSM15X (TPR15X)Number of Rails: 2Fits: M16/AR15/M4/ With A style front sightMade of: AluminumWeight (oz.): 2.56/1.6Width (in.): 1.375"Length (in.): 2.875"Height (in.): 0.875"