The Orient RA-AC0K01B (also referenced as RA-AC0K01B10B / AC0K01B) is a robust, high-performance Japanese automatic diver-style watch from Orient’s renowned Sports Collection. Globally recognized among watch collectors and dive watch enthusiasts by its famous series nicknames—the "Triton" or "Neptune"—this 43.4mm timepiece pairs a solid stainless steel case with a deep matte black dial, a offset screw-down crown positioned at 4 o'clock, an in-house automatic movement, a premium scratch-resistant sapphire crystal, a 120-click unidirectional rotating bezel, and a solid stainless steel construction. Designed for active men who require professional dive-tool functionality, ergonomic wrist comfort, and rugged sport aesthetics, it stands as an exceptionally reliable mechanical timepiece. The defining visual highlight of this RA-AC0K01B reference is its high-contrast matte black dial framed by a black 120-click unidirectional bezel. Set beneath a premium flat sapphire crystal, the dial features bold circular and baton hour indices filled with potent luminous material for low-light legibility, broad arrow and sword hands, a calendar date window at 4 o'clock, and the signature offset crown placement at 4 o'clock to prevent the crown from digging into the back of the wrist during physical activity. The clean monochrome contrast between the black dial and radiant luminous markers gives it an assertive, highly functional tool-watch look. Beneath its rugged dive housing, the watch is powered by Orient’s reliable in-house Caliber F6722 automatic mechanical movement with hand-winding and second-hand hacking capabilities. Operating at 21,600 vibrations per hour (3 Hz) across 22 synthetic jewels, this self-winding caliber delivers a dependable 40-hour power reserve with a daily precision accuracy rating of +25 to -15 seconds per day. The case features well-proportioned sport-diver dimensions, measuring 43.4mm in case width (51.0mm lug-to-lug) with a profile thickness of 12.8mm and a 22mm lug width, providing a stable and planted presence on the wrist. Dial protection is provided by a scratch-resistant sapphire crystal that maintains optimal clarity under harsh conditions. Built for aquatic sports and physical activity, the solid stainless steel case incorporates an ergonomic 4 o'clock screw-down crown, crown guards, and a solid screw-down caseback, achieving a certified 200-meter (20 bar / 660 ft) water resistance rating suitable for swimming, water sports, and recreational diving. The timepiece comes completed on an integrated stainless steel link construction, secured by a solid fold-over deployment clasp with a double push-button safety catch
