Used for ship with length more than 50M when night navigation,life time is more than 700hours, seal structure and waterprooffeature.Confirm to THE INERNATIONAL REGULATIONS FOR PREVENTION COLLISION AT SEA 1972 AND GRADE ENTRY NORMS FOR STEEL SHIPS.Confirm to the International Stardard IEC60598-1-2008.Confirm to the standard of marine electric signal light's technical condition GB/T 3028-2012