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.
Seiko's and Japan's first ever diver's watch was made in 1965 at a time when watches with high levels of water resistance were not widely available. It incorporated an automatic mechanical caliber and delivered 150m water resistance. The watch was designed for maximum reliability and legibility in the harshest conditions and was used by the Japanese Antarctic Research Expedition from 1966 to 1969.
As leisure diving grew in popularity, the watch found favor with an ever wider public and set Seiko on a path of continuous development in durable, accurate and safe diver's watches that has continued to this day.
The Prospex re-creation of this 1965 classic is faithful to the original design, but thoroughly up-to-date in its technology. It incorporates 10-beat Caliber 8L55 is made by Seiko's skilled craftsmen and women in the Shizuku-ishi Watch Studio in Morioka in the north of Japan. The case is virtually identical to the original, but its diameter has been increased by 1.9mm.
While faithful to the 1965 design, this new Prospex diver's watch has greatly enhanced functionality. It has a box-shaped sapphire crystal and 200m water resistance for greater reliability. Durability is also enhanced by the super-hard coating which protects the watch from scratches. The case back bears the same dolphin emblem as the 1965 original.
Caliber Number:8L55 High Beat
Movement Type:Automatic with manual winding capacity
Accuracy:+15 to -10 seconds per day
Duration:Approx. 55 hours
Case Material:Ever-Brilliant Steel
Crystal:Box shaped sapphire
Crystal Coating:Anti-reflective coating on inner surface