RITCHIE Helmsman Flush MountSpecifications: 3 3/4″ (95 mm) Open Face Dial or CombiDial *All hardware included where applicable. Features: 3 3/4″ (95 mm) Open Face Dial or CombiDial Easily Installed, Fits 4″ (102 mm) Mounting Hole. Click here to view a template of the mounting hole (NOTE: Adobe versions may differ; download and print the template to actual size). Replacement Mounting Gasket Use HL-0105 mounting gasket when an adapter ring is installed on the compass Exclusive Built-in Green NiteVu Night Illumination Built-in Compensators to Easily Adjust for Deviation Scientifically Matched Sapphire Jewel and Hardened Steel Pivot Dial Movement Powerful DirectiveForce Magnets for Fast Heading Lock-on Movable Sun Shield 45 Degree Lubber Lines High Temperature Composite Construction for Extended Operating Range Adapter Rings Available. Sold separately. 6″ (153 mm). Retrofits Existing Mounting Hole for; Model No. HF-72 & HF-73 order H-ABLK. For Model No. HF-72W & HF-73W order H-AWHT. 100% Repairable Exclusive 5-Year Ritchie Warranty