The Trijicon MRO 1/3 Co-Witness Quick Release mount features a Mil-Spec drop test rated 7075-T6 aluminum design, with a easy to use one handed tool less mounting Return to Zero features in a low weight, low profile design which works with any Picatinny rail.This means that the MRO is mounted higher than the iron sights resulting in a clearer field of view. The iron sights remain visible in the lower 1/3 of your optical window for use as a backup.