The MBUS 3 Sight – Front back-up sight provides the durability and light weight of our original MBUS in a smaller polymer package that takes up even less space on your rifle. It stows at just .47” tall and 1.38” wide on your M1913 picatinny rail and mitigates snagging when you’re on the move. The spring-loaded MBUS 3 is ready for quick, ambidextrous deployment, and includes tool-less elevation adjustment and two front-post width options for different shooting scenarios.