Made in the USA, The MBUS Pro (Magpul Back-Up Sight) is a corrosion resistant all-steel back-up sighting solution. The dual aperture, windage adjustable rear and no-tool, elevation adjustable front excel in all 1913 Picatinny rail mounting applications, including rail-height gas blocks. Positive detents keep the MBUS Pro Rear at standard AR sight height when deployed, and low when it is stowed. The steel rectangular site post are selectable between match and standards widths, and the sight is case hardened and finished with Melonite QPQ for extreme resistance to wear and corrosion.