The IWC Portofino 3513 is a classical gentleman's watch with self-winding movement that was available from the late 1980's to the early 2000's. Its case, in yellow gold or stainless steel, measured 34mm across, housing either a caliber 37521 or 30120 movement depending on the year of production.Reference IW3513-03 has a Yellow Gold case and a Black military / pilot-style dial.