USED XS Sight Systems Big Dot Tritium Shotgun Sight Bead on Plain Barrel Yellow Standard. Fits Benelli M1 and Uses the Factory Attachment Nut to Install. Big Dot Demands Your Attention - Aiding in Rapid Alignment and Indexing on the Threat. White Dot Reflects Ambient Light for Best Visibility in Low Light Or Shadows While the Center Tritium Vial GloWS Green in Low to No Light Making It the Perfect Front Sight Upgrade for 24/7 Use. Outside Diameter Big Dot 0.188in Specifications for XS Sight Systems Big Dot Tritium Shotgun Sight: Manufacturer: XS Sight Systems Illumination Type: Tritium Illumination Color: Green Fabric/Material: Tritium Additional Features: Big Dot's Outside Diameter is 0.188in Gun Type: Shotgun Features of XS Sight Systems Big Dot Tritium Shotgun Sight: Steel Sight With Blued Finish; Green Tritium; White Ring Front; Snag-Free Design; No Questions Asked Warranty Package Contents: XS Sight Systems Big Dot Tritium Shotgun Sight XS Sight Systems SG-2005-3Y: Big Dot Tritium Shotgun Sight Bead on Plain Barrel Yellow Standard