The RS Riflescope Lens Shade reduces sun and oblique light glare to help improve clarity, while adding increased protection to the objective lens. The lens shade screws directly onto the objective end of all RS.1, RS.3 and RS.4 Riflescopes. RS.1 -Length: 50.8mm -Diameter: 50.8mm -Weight: 0.9 oz RS.3 -Length: 76.2mm -Diameter: 58.74mm -Weight: 2.2 oz RS.4 -Length: 76.2mm -Diameter: 65.09mm