NcStar VISM Pro Series Flip-Up Rear Sight

Features:Pro Series Flip-Up Rear sight is a low profile spring loaded rear back-up sight that flips-up and deploys with a push of a button.Rear sight low profile design folds flat to fit under the majority of scopes.Features an A2 dual aperture (large & small) that is fully adjustable for windage. Knurled windage knob makes adjusting the windage an easy task.Dimensions: 2.4"L X 1.2"W X 0.8"HWeight: 2.3 oz.Aluminum main body with steel A2 dual rear aperture, windage knob, and adjustment screw.Mounts onto Picatinny Mil-STD 1913 rails, mounting tool included.US. PAT. 9976834