Direct replacement for M16A2-style dual aperture sights | Both large and small apertures are on the same plane | Compensates for lateral movement on the windage screw while switching between apertures | One zero for both apertures with no point of impact shift | Large (0. 208” I. D. ) aperture for quick sight acquisition in close quarters or low light | Small (0. 081” I. D. ) aperture for longer, more accurate sighting of distant targets | MIL-SPEC manganese phosphate finish | Made in the USA