The Wheelmark approval is for Lifeboat and Rescue boat compasses. These compasses are also suitable for sailboats, power boats and motor sailing vessels. Designed for powerboats up to 28′. 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. High temperature composite construction for extended operating range. 45 Degree lubber lines. 100% repairability. Exclusive 5-year Ritchie warranty.