Brand: Croton

Model: Chronomaster Aviator Sea Diver Chronograph ref. 9870 (Valjoux 23 movement); case #105-27627; Swiss Made circa 1960s

Case: Solid stainless steel case with screw-down back is approximately 38mm excluding the original unsigned winding crown

Strap: 20mm handmade smooth calfskin strap with contrast stitching and 16mm polished stainless steel tang buckle

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

Features: Stunning original matte black dial with beveled shiny black sub-register rings and gorgeous yellow Tritium hour markers; outer tachymetre scale for calculating the average speed of a moving object over time (i.e. for 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 unpolished 38mm stainless steel case with domed acrylic crystal; high-grade Valjoux 23 column-wheel chronograph movement; very desirable Chronomaster model

Condition: Fantastic original condition overall with only minor honest wear consistent with age and use; sharp stainless steel case is completely unpolished with defined bevels on each of the lugs; crisp caseback remains clearly legible with "Ronnie Estill" professional engraving in the center (Ron enjoyed all things planes, trains, and boats); clean original black rotating bezel; flawless original matte black dial with all Tritium luminous material in tact and matching; beautiful shiny black stepped sub-register rings and vibrant red yachting regatta countdown; excellent original hands; original minute hand lume has aged slightly darker; new domed acrylic crystal matches the profile of the original acrylic crystal

Other: Designed and built for land, sea, and air, the Chronomaster has become a favorite within collector circles today - So much so that the Nivada Grenchen brand was re-booted specifically to re-issue these iconic watches. Thanks to a small group of dedicated Chronomaster experts and scholars, we also have an entire book dedicated to the model's history and lineage: CHRONOMASTER ONLY. 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 too busy...

Croton (and Nivada Grenchen) produced many variations of the Chronomaster and this particular reference 9870 is in top condition and one of the most desirable iterations. Reference 9870 is easily distinguishable by its shiny black stepped sub-register rings, which look so much better and more dynamic than the "flat" matte registers. It features lume dots similar to the Omega Speedmaster. The "5-4-3-2-1-0" countdown numerals printed within the red minute sector are used for regatta racing. We love the small "alpha" register hands and awesome broad-arrow hour hand. The overall design is very balanced and looks absolutely killer on the wrist! The 9870 is powered by a high-grade Valjoux 23 movement, which is based on the legendary Valjoux 72 (but in two-register format). It comes with smooth column-wheel activation. For peace of mind, our watchmaker has completely overhauled the movement with a new acrylic crystal and gaskets (in the crown, pushers, and caseback) installed at the time of service.