XS Big Dot front sight features a green Tritium insert surrounded by a thick white line. The Tritium vial improves low light shooting and the large white outline makes daytime sight acquisition fast. This sight is designed to be epoxied onto the factory #6 sight bead on a pedestal. The sights will work with a .125 – .140 diameter bead. If your shotgun is not equipped with this size bead one will have to be installed.