The FAB Defense Deployable Front and Rear Sights are an advanced, dual aperture, durable and low-profile auxiliary sight set. It was designed for more accurate aiming and faster target acquisition. Windage is easily and quickly adjusted without tools. RBS is readily mounted on any 1913 Picatinny rail, making it ideal for use on M4 / AR-15 / M-16 platforms and on the FAB Defense K.P.O.S. FeaturesCan be used as a primary or back-up sightErgonomic angel-wing-shaped front shroud helps center the image with any rear sight, but when used with a matching FAB Defense RBS Rear Back-up Sight, it creates a precise optical tunnel that ensures more accurate aiming and faster target acquisitionLow folded profile is smooth and inconspicuous, and will not snag on gear, webbing, or brushInstant spring-locked deployment mechanism will not slip, break or deformNo tools needed for easy, rapid elevation adjustments, with positive detent lockingMade of extremely durable high-grade polymer and metal