Seiko 55th Anniv Limited Edition 1968 High Beat Marinemaster 300M Men's Watch SLA039J1Seiko 55th Anniversary Prospex Limited Edition 1968 High Beat Marinemaster 300M Men's Watch SLA039J1 55 years ago, Seiko introduced its, and Japan's, first ever diver's watch. With an automatic movement and water resistance to 150m, it proved its reliability when it was used by members of the Japanese Antarctic Research Expedition from 1966 to 1969. In the years that followed, Seiko created many other diver's watches that found favor with professional