Brand: Nivada Grenchen

Model: Chronomaster Aviator Sea Diver Chronograph ref. 85004/3181; rare variation with grey sub-registers and Valjoux 23 movement; Swiss Made circa 1960s

Case: Solid stainless steel case with screw-down back is approximately 38mm excluding the original signed Nivada "N" winding crown (24 teeth)

Strap: 20mm handmade tan calfskin strap with polished stainless steel tang buckle

Movement: Valjoux cal. 23 manual-winding chronograph movement (17 jewels) with column-wheel activation; 18,000 BPH; Swiss Made

Features: Stunning original matte black dial with grey sub-registers and Tritium hour markers; outer tachymetre scale for calculating the average speed of a moving object over time (i.e. during racing applications); 30-minute chronograph recording capability and red 5-minute yachting regatta countdown; cool original broad-arrow hour hand; original "alpha" sub-register hands; original rotating bezel displays elapsed time (i.e. during dives) and can track a second time zone; large 38mm stainless steel case with domed acrylic crystal; high-grade Valjoux column-wheel chronograph movement; rare Chronomaster model variation

Condition: Very nice condition overall with minor wear consistent with age and use; solid stainless steel case remains thick and sharp with great bevels on each of the lugs; crisp "medallion" caseback is clearly legible; very attractive original matte black dial exhibits a few minor dark stains; excellent grey sub-registers and vibrant red yachting regatta countdown; original Tritium hour markers have aged to a creamy yellow hue; original luminous hands do not react to UV exposure and appear to have been color-matched to the dial at some point; original rotating bezel shows some wear from use; clean domed acrylic crystal

Other: Designed and built for land, sea, and air, the Chronomaster has quickly become a favorite within collector circles today - So much so that a small group of experts/scholars recently collaborated to release CHRONOMASTER ONLY, an entire book dedicated to the model's history and lineage. Original catalogs and brochures dubbed it the "Super-Chronograph" because it could do so many things. From yachting to diving to racing to flying (and everything in between), one can see why professional sailors, aquanauts, drivers, and pilots alike preferred the Chronomaster as their go-to timekeeper. It's astonishing how the Chronomaster manages to pack so many features into one watch without it being gaudy and over-the-top.

Nivada (and Croton) produced many variations of the Chronomaster and this particular reference 85004/3181 is one of the more attractive and desirable iterations. It was the very first Chronomaster model to feature grey sub-registers and is easily distinguishable without the "5-4-3-2-1-0" countdown numerals printed within the red yachting regatta sector. We love the small "alpha" register hands and awesome broad-arrow hour hand. This particular reference is powered by a high-grade Valjoux 23 manual-winding movement with smooth column-wheel activation. The overall design is very balanced and looks absolutely killer on the wrist!