While faithful to the original designs, all three watches are fully up to date in their specifications and execution. The greatest advance is in the grade of stainless steel used in the construction of the three watches. To be known as Seiko's "Ever-Brilliant Steel," thanks to the brilliant white hue that gives this trilogy of watches its unique look, this grade of steel is more corrosion resistant than that which is used in most high-end watches today.* It is used for the first time** in the watch industry for the cases of the 1965 and 1968 re-creations and the bezel of the 1975 re-creation whose case is, like the original, in titanium. This material is used extensively in the surfaces, linings, bolts and other components of marine structures and vessels so as to avoid corrosion in a chloride-rich environment such as sea water. It presents many challenges in the manufacture of watch cases but, thanks to the experience and innovative techniques of the Seiko team, these challenges were overcome and Ever-Brilliant Steel is now set to bring a new level of durability to the diver's watch.
The 1965 and 1968 re-creations are powered by the high beat 8L55 movement and the 1975 re-creation carries Caliber 8L35, both developed and assembled expressly for diver's watches at the Shizukuishi Watch Studio. All three have sapphire crystals with anti-reflective coating on the inner surface. The 1975 re-creation has an increased anti-magnetic resistance of 40,000 a/m thanks to the dial made of pure iron.
* This stainless steel has a PREN (Pitting Resistance Equivalent Number) value 1.7 times higher than that of the grade of steel used in most high-end watches. PREN is a widely accepted standard used to measure corrosion resistance. ** as of December 2019, based on Seiko's research.
It all began with a letter from Hiroshima. The correspondent, a professional diver, explained that no watch could withstand the stresses and strains he experienced when working at depths greater than 300m. Inspired, Seiko engineers got down to work. Years of research development paid off in 1975 with the introduction of the world's first titanium cased diver's watch: the Professional Diver's 600m.
This model has a titanium one-piece case and an outer case protector as same as 1975 original. The case construction and dial layout are loyal to the original, as are the unique hour markers and the crown, while the water resistance has been increased to 1,000m. The outer case material is zirconia ceramic which is seven times harder than steel protecting the case from shock.
It features all the innovations that Seiko brought to diver's watches in the 1970's, including the double layer construction with one piece inner case, the L-shaped gasket for helium resistance and the accordion-style strap.
Movement Type:Automatic with manual winding capacity
Accuracy:+15 to -10 seconds per day
Duration:Approx. 50 hours
Case Material:Titanium with Ever-Brilliant Steel
LumiBrite:Lumibrite on hands, indexs and bezel
Water Resistance:1000m / 3300ft for saturation diving