Bead Sight: Simple round bead set into the top of the barrel near the muzzle of a shotgun. Some shotguns have a second, smaller bead about halfway back on the barrel. The shooter uses the shotgun to “point” at and follow a moving object. The bead is used only for a reference as the shotgun is pointed and moved to follow flying or running targets.
Open (Iron) Sight: Combination of a bead or post front sight and a notched rear sight. These sights are simple and inexpensive. Open sights allow quick sighting. To aim, you center the top of the bead or post within the notch of the rear sight, and line up on the target. Open sights can be fixed or adjustable.