Note this is the four piece kit containing Four sights - Red and Green for the Remington and a Red and Green for Other models. So you get four bases with fiber optic tube installed in them.
If you want to increase your accuracy in the field whether your hunting upland birds, waterfowl or turkeys get the patented Front Shotgun Sights by Allen. They are designed specifically to fit 5/16 Remington and Benelli 12-gauge guns and fits most Browning BPS guns. The frame is spring steel which clips onto the top rail and the blade is fiber optic material in red or green color. Compatible with 1/4", 5/16", 3/8" ribs. Contains Green Red fiber optic sight. Low profile, fits over the vent rib.