#html-body [data-pb-style=N3UCRVG]{justify-content:flex-start;display:flex;flex-direction:column;background-position:left top;background-size:cover;background-repeat:no-repeat;background-attachment:scroll}This Nc Star MARDRS Ar15 Detachable Rear Sight will fit virtually all AR-15, M4, and M16 flattop Picatinny rail upper receivers. The Nc star Detacheable Rear Sight is fully adjustable for elevation and windage by adjustable controls. In addition, is it small enough, youll be able to not only mount a red dot sight but HOLO sights as well. AR-15 Detachable Rear A2 Iron Back-Up Sight (Dual aperture) Precision Made Fixed A2 Design - Adjustable fo Windage and Elevation Mounts onto Weaver & Picatinny typ rails Aluminum & Steel onstruction Length: 2.7" Weight: 5.1 oz