Seiko SLA055J1

The overall design of this watch is inspired by the Seiko 1968 Diver’s 300m watch – which was powered by the highest of world standards hi-beat calibre and was worn for the first-ever Japanese Mount Everest expedition.

In this modern version, several technical specifications have been upgraded and updated. The watch features the high-grade 8L35 mechanical calibre which was specially designed for diver’s watches. Consisting of 192 parts created with precise machining techniques, this timepiece is hand-assembled and adjusted by watchmakers at the Shizukuishi Watch Studio in Morioka in the north of Japan.

The case, bezel and crown are all made from Seiko’s exclusive “Ever-Brilliant Steel” – with its brilliant white hue, this grade of steel is more corrosion resistant than that which is used in most high-end watches today.* To further ensure the watch’s durability, the crown is not screwed directly into the case but locked into a separate component that is built into the case and so can be more easily replaced.

Prospex is a combination of the words ‘Professional’ and ‘Specifications.’ These timepieces are designed to be practical, reliable and durable within extreme or everyday environments, for experts, sports lovers and adventure seekers alike. Since launching Japan’s first diver’s watch in 1965, Seiko’s innovative watchmaking has changed global dive watch standards.

*This material is used extensively in the surfaces of marine structures and vessels because of its extreme corrosion resistance in sea water. It 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.