Prospex Marinemaster 1965 Heritage Diver’s Watch. Distinguished by its blend of functionality and aesthetics, this extraordinary timepiece, part of the first globally launched watch series to bear the “Marinemaster” name, features the first see-through screwdown caseback on a Seiko diver’s watch, as well as an elegantly chamfered case and bezel and a flexible double-curved bracelet for a comfortable fit. Based on Seiko’s and Japan’s first diver’s watch from 1965, this exceptional timepiece extends the Prospex tradition of celebrating its rich legacy of innovation in high-intensity timekeeping by re-creating and re-interpreting signature achievements with today’s finest technology and materials. Visible beneath the caseback, the thin, but exceptionally accurate, 26-jewel 6L37 movement beats at a frequency of 28,800 vibrations per hour and provides a power reserve of approximately 45 hours and manual winding capability. Framed by a uni-directional rotating elapsed timing bezel, the distinctively patterned grayish- green dial offers LumiBrite hands and markers. As rugged as it is stylish, this premium diver’s watch, following ISO standards for scuba diving, is crafted of stainless steel with a durable super-hard coating and features a box-shaped sapphire crystal with anti-reflective coating on the inner surface, screwdown crown, and a tri-fold push button release clasp with secure lock and extender.