3-3/4″ Dial. Mounting Hole: 4″. Black. PowerDamp Plus, High-Visibility Blue Dial with extra large white numerals. 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. Internal gimbal systems for maximum stability during adverse pitch and roll conditions. Powerful DirectiveForce magnets for fast heading lock-on. Movable sun shield. 45 Degree lubber lines. High temperature composite construction for extended operating range. Custom fitted protective covers available. Easily installed. 100% repairability. Exclusive 5-year Ritchie warranty.