These BUIS sights front and rear flip-up sights for the AR 15 rifle are ideal for DPMS, Colt, Smith & Wesson M&P 15 tactical, Bushmaster Bravo Zulu A4 upper flat-top receiver. The AR 15 iron sight sets include both low-profile, spring-loaded A2 front and rear sight. The AR 15 iron sight sets include both low-profile, spring-loaded A2 front and rear sight. This set of AR 15 back-up iron sights flips up with the push of a button. The front sight features an A2 front sight post that is fully adjustable for elevation. Front sight height is designed for handguard rails, monolithic receivers, and gas blocks that are at the same height as the AR receiver Picatinny rail. The rear sight features an A2 dual aperture (large & small) that is fully adjustable for windage. The knurled windage knob makes adjusting the windage an easy task. The rear sight's low-profile design folds flat to fit under the majority of scopes. This AR 15 sight set fits any Picatinny Mil-STD 1913 rail and comes with a mounting tool. Front Sight Dimensions: 2.4"L X 1.1"W X 0.8"H. Rear Sight Dimensions: 2.4"L X 1.2"W X 0.8"H. This AR-15 back up sight set are made from strong aircraft grade aluminum with a steel A2 front post and an A2 rear aperture. Vism Limited Lifetime Warranty.