Important Swiss gold lever chronometer Circa 1946/1990

Lever with Guillaume balance and one minute tourbillon 
–
An extremely fine, rare and important Swiss 18 carat gold open faced keyless lever pocket chronometer with guillaume balance and one minute tourbillon, circa 1946 and 1990. Encased and sold in 1990. Tourbillon nickel finished lever movement manufactured in 1946, 18 jewels, Guillaume balance, polished steel three armed tourbillon cage. Silvered dial, applied gold baton numerals, gold dauphine hands and subsidiary seconds. Massive plain case, double stepped bezel, glazed display snap on back. Case, dial and movement signed, case and movement  numbered. Comes with Bulletin d’Observatoire, certificate, sales tag and box.
–
Diameter: 62 mm
–
Signed: Vacheron Constantin Genève Swiss