TruGlo Universal Pro Series Red Shotgun Sight helps eliminate problems with eye dominance. Promotes shooting with both eyes open. Extremely low profile. Easy installation. Universal - fits any rib width. Quick target aquisition. Fiber Diameter: 0.078 inch. Universal fit front sight for vent rib barrels. The sight has a low profile design that easily attaches to the vent rib. The fiber optic is protected in the sight base but still collects an ample amount of light. The fiber is .078" in diameter and fits any rib width with easy installation.