Citizen Promaster Mechanical Diver / Fujitsubo Watches

The Promaster Mechanical Diver / Fujitsubo series revisits the legendary 1977 Challenge Diver model, recovered after years underwater and still fully functional. These modern models feature a Super Titanium™ case with Duratect treatment for superior scratch resistance, an anti-magnetic caliber 9051 automatic movement, water resistance to 200m according to ISO 6425 standards, and a sleek design suitable for both sporty and urban wear.

The NB6021-68L features a deep blue dial and a matching strap. The NB6021-17E offers a black dial on a rubber strap, with a vintage feel and retro-style luminescent green hour markers. The NB6025-59H plays on a "stealth/DLC" theme with a dark DLC-treated case and a gradient gray/black dial, a darker version of the series. Together, these models embody robustness, performance, and heritage.

Common technical characteristics & variations

• Movement: Caliber 9051, automatic, 4 Hz (28,800 A/h), power reserve ~ 42 h

• Antimagnetic / resistant to magnetic fields: movement and components designed to withstand fields up to approximately 16,000 A/m (Type 2)
  

• Casing / Material: Super Titanium™ with Duratect treatment (TIC or DLC depending on version)

• Thickness / Dimensions:
  • NB6021-68L / NB6021-17E: ~41 mm in diameter, ~12.3 mm thick
  • NB6025-59H: same size (41 mm), DLC/dark grey finish for the dark version

• Glass: sapphire with anti-reflective coating

• Water resistance: 200 m / 20 ATM (ISO Diver certified)

• Bracelets / materials depending on version:
  • NB6021-68L: matching Super Titanium bracelet
  • NB6021-17E: black polyurethane (rubber) strap
  • NB6025-59H: Matching Super Titanium DLC bracelet / dark tone

• Functions: hours, minutes, seconds, date at 3 o'clock

• Special features / Design:
  • Legacy of the 1977 Challenge Diver (restored from a shoreline, still functional) inspired the Fujitsubo reissue
  • Durable finish: Super Titanium cases + Duratect treatments for scratch resistance
  • Luminescent index/hands (high contrast) for readability in low light