OMB's Express Police Supply

New flip up rear sight made by Yankee Hill Machine. Model YHM-9440. Bushmaster uses these. Mount on picatinny rail. An aircraft grade aluminum, flip-up auxiliary sight featuring dual apertures, 1/2 M.o.A. windage adjustment, black anodized finish, convenient right hand adjustment knob and full height sight apertures. Height when folded is 1/8", lower than similar designs.