French platinum onyx, enamel and diamond set watch Circa 1930

Platinum keyless watch by Cartier
–
A fine French platinum onyx, enamel and diamond set open faced keyless watch with enamel and yellow gold chapter ring, circa 1930. Manual wind nickel finished lever movement, 19 jewels, bimetallic compensation balance.
Silvered matte dial with Arabic numerals and Roman outer, blued steel Breguet hands. Case with onyx, platinum bow, enamel and yellow gold outer chapter ring secured by 4 screws, case back decorated by platinum and diamond set pattern dial signed Cartier.
–
Diameter: 48 mm
–
Signed: Cartier