The AR-15 flip up sight is a folding iron sight that mounts to a Picatinny or Weaver rail on an AR-15. Shooters press a button or lever to deploy it for aiming, then fold it flat when running an optic. It works as a primary or backup sighting solution on any AR-15 build. The sight fits standard rail systems on upper receivers and handguards. Builders choose an AR-15 flip up sight to keep iron sight capability without blocking the view through a scope or red dot.