Magpul MBUS PRO Steel Backup Sights All steel construction; steel, rectangular sight post selectable between match and standard widths (.040" Match width for increased precision; .060" Standard width for maximum visibility) Case hardened and finished with Melonite QPQ for extreme resistance to wear and corrosion Mounts on any MIL-STD-1913 Picatinny/STANAG 4694 rail including receiver-height gas Blocks Elevation adjustment knob - no tools Required Positive detents in both the up and down positions as well as on the elevation knob; Standard sight height when deployed All steel construction Case hardened and finished with a ferritic nitro carburizing process for extreme resistance to wear and corrosion Mounts on any MIL-STD-1913 Pica tinny/STANAG 4694 rail Windage adjustable with low-profile knob - no tools required Back-Up Sight Rear