AR-15 Flip Rear Sight- Features of this sight include: a rugged but lightweight design with a steel base, a quick release thumb screw, and aluminum stem. Locks in the deployed position with ease and takes up very little space on the upper receiver.Features : 1/2 M.O.A. and comes with a standard rear peep aperture Mounts to any picatinny rail Designed to co-witness with the standard M16-M4 front sight