Seiko Prospex Marine Master \'MM300\' Diver\'s Automatic Blue Ocean Dial Silver Stainless Steel Men\'s Watch SLA023J1 Since Seiko made its first diving watch in 1965, Seiko has been exceeding the expectations of those whose sports require watches with professional specifications. Drawing from Seiko\'s roots, a \'Sumo\' series has become popular among Seiko fanatics. Sumo wrestling is the national sport of Japan. Once patronized by the emperors, Sumo\'s origins go back at least 1,500 years, making it the world\'s oldest organized sport. The piece is so named due to its thick case style resembling that of a wrestler. Style: This Seiko Prospex Marine Master \'MM300\' SLA023J1 takes inspiration from the very watch which unlocked the deep, the Rolex Submariner. Silver indexes and hands compliment a blue dial reminscent of the ocean. Functions: Both the indexes and hands are coated in a luminous material to provide clear visibility at depths of the ocean. Moreover, the ever present Seiko logo can be seen at 12 with a date window at 3. Then, a silver stainless steel case with a blue bezel ontop surround the dial to provide it with protection and class. Then, a silver stainless steel bracelet fastens using a fold over clasp. A 8L35 caliber automatic movement giving you a 50 hour power reserve.   This watch has a water resistance of 300 metres, making it suitable for diving. Made In Japan: Firstly, for all you Seiko enthusiasts, this premium timepiece has been made in Japan, indicated by the suffix ‘J’. Seiko watches made in Japan are hard to obtain outside of Japan due to the highest quality of craftsmanship and astonishing features that come in each individual timepiece. We have a range of Japanese watches here at Watchnation but in limited quantities, so if you are looking to add to your collection then this is the perfect place for you. Key Features: 8L35 Caliber Auto + Manual Winding +15 to -10 Seconds Per Day 50 Hour Power Reserve Stainless Steel Case Ceramic Bezel Sapphire Crystal Anti Reflective Coating Lumbrite Hands & Indexes 3 Fold Clasp & Lock  300m Water Resistance  One Piece Structure Screw-down Crown Undirectional Rotating Bezel 26 Jewels Date Display Stop Second Hand Function Free Rubber Strap   The Prospex Story: Scuba-diving became increasingly popular around the 1960’s, an example of this was the formation of the Professional Association of Diving Instructors (PADI) in 1965. Moreover, diving equipment was becoming increasingly reliable, so more people began to dive recreationally. There was of course a crucial need for divers to be able to time their dives. Subsequently, the watch market responded to this necessity by flooding the market with reliable dive watches. In 1965, Seiko first produced their original dive watch - the 6217. This was the very first Japanese dive watch and it paved the path for future divers that claim to meet Seiko’s Professional Specifications. The original 6217 was notably worn by the 8th Japanese Antarctic expedition. This model featured bidirectional rotating bezel, legible lumed hands, and an easy-to-grip crown. Although professional divers were still pining for a dive watch that had the capability of going deeper than 300 metres. The Seiko development team went about going to produce a watch which was capable of doing so. The year 1975 marks the release of the first Seiko Prospex, with the ability to be used in 600 metres of depth. The Prospex is the first diver watch to use a titanium case instead of standard steel. It was also the first to use a ceramic shroud for deep-sea diving and the first to use a hybrid analog digital watch with an alarm. Another achievement for the Prospex family was the L-shape single crystal gasket, which prevented any helium escape valve unnessacary. This was one of the development teams first aims, to prevent a helium resistant watch. There were numerous other milestones that Seiko achieved with the Prospex. Such as in 1986 when Seiko produced a watch that was water resistant to 1000 metres. The Brand: Seiko Seiko’s story began in 1881 with the opening of a shop in Tokyo, it’s owner was Kintaro Hattori. Eleven years after the opening of his shop, Hattori opened a clock factory in 1895 that they began to produce pocket watches. Soon followed by alarm clocks in 1899, and then table clocks in 1902. Then in 1913 Hattori began working on his first wristwatch. Then in 1924, the brand Seiko was born with the creation of the first Seiko wristwatch. Seiko established itself throughout the 20th century as being a force in the advancements that took place in the watching world. For example, Seiko were the producers of the first winding wristwatch made in Japan. Then in 1964, Seiko became the official timer for the Olympics. And then most notably Seiko unveiled the first quartz wristwatch, the Astron, in 1969. Marking the beginning of the quartz revolution. Or equally impressive the creation of the world’s first TV watch in 1982. And even more relevant today, with our abhorrent use of non-renewable energy sources, Seiko’s Kinetic. This watch had the ability to generate its own power from the movement of the wearer. If you have any questions please  click here Click here to join our  facebook  and  Instagram !