Magnetically attached, highly visible fiber optic sight provides exceptional sight acquisition in all light conditions. Features four different bases with different internal mounting dimensions that fit a variety of ventilated ribs. Polymer base snaps onto the rib and is held firmly in place with a high-strength magnet for quick installation without screws. Includes one red, green, yellow, and amber fiber optic rod. Rods are easily interchanged using thumb and finger pressure. Notch in base uses factory bead to locate sight correctly along bore axis. Two sets of magnets allow mounting sights on two shotguns with different width ventilated ribs.Universal fit for all shotguns equipped with ¼" (6.4mm), 5/16" (7.9mm), 3/8" (9.5mm), or ½" (12.7mm) wide ventilated ribs. Includes one base of each size.