Official Product of Ultimate Arms Gear, Brand New. Bright High Visibility Glowing Fiber Optic Sight (Fiber Diameter 2mm or .078") - No Batteries Required.Quickly & Easily Snaps In Place Behind Factory Front Bead On Plain Barrel 12 & 20 Gauge Shotguns. Notch in base uses the factory bead to locate the fiber optic sight correctly along bore axis. Ultra durable construction & low profile design.An Excellent Tactical Upgrade For a Home Defense Shotgun - No Gunsmithing Required.