TriViz fully adjustable sight set. The triangular sight picture has a natural sight alignment and allows a full view of the target. Fully adjustable rear sight for windage and elevation. Fits most shotguns with ventilated ribs from 1/4 to 3/8 wide with removable front beads. Fits vent-ribbed shotguns from 1/4 to 3/8 (6.3mm to 9.7mm) with removeable front bead.