Magpul MBUS PRO Offset 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 height over bore when deployed, 45 deg. offset right-hand side