very rare Rolex, so called "Bombay".
in 18 ct. red gold case ca.1956 Ind.nr. 193XXX. Case polished but numbers readable with loupe.
The name "Bombay" was created in collector circles from the actually applicable "Bombe" french for domed - in this case the lugs.
Many of these Bombay models were produced in 14 ct. for the American market, so 18 ct., and red gold at that, is extremely rare.