MaTech Mil-Spec Back-up Iron Sight (B.U.I.S)
The Picatinny Backup Iron Sight, manufactured by MaTech is the standard issue BUIS for all new and fielded U.S. Military M4 carbines and M16 flat top rifles. Rigorously tested at Fort Benning and Aberdeen Proving Grounds, our product has the strength, durability, and accuracy to meet your sighting requirements.NSN 1005-01-484-8000