Cartier lady wristwatch circa 1920

Rare ladies' wristwatch, signed Cartier, circa 1920, square "Cocktail" model in 18-carat yellow gold and platinum with bezel set with rose-cut diamonds. Original mechanical movement signed European watch and Clock Co. Maker's mark of Edmond Jaeger. Black satin strap with 18-carat gold folding clasp signed Cartier (later).