IWC REF. 3750 DA VINCI PERPETUAL CALENDAR CHRONOGRAPH YELLOW GOLD International Watch Co., Schaffhausen, "Da Vinci," case No. 2640156, Ref. 3750. Made in 1997. Very fine, self-winding, water-resistant, 18K yellow gold wristwatch with round button chronograph, registers, secular perpetual calendar, moon phases and an 18K yellow gold IWC buckle. Accompanied by the original fitted box, warranty, instruction booklets and an IWC overhaul receipt dated February 27, 2013. Two-body, solid, polished and brushed, rounded stepped bezel, screwed-down winding crown, snap-on case back engraved: ROBERT E. DARBY, FROM HIS PARTNERS, 12-23-97, hooded mobile lugs, hesalite crystal. White with applied yellow gold faceted baton indexes and luminous dots, outer 1/5th seconds track, subsidiary dials for the seconds, the 12-hour and 30-minute registers, days of the month, of the week, apertures for the moon phases and for the year display with 4 digits until 2499. Luminous gold baton hands. Cal. 79061, gilt brass, 36 jewels, straight-line lever escapement, monometallic balance, adjusted five positions, shock absorber, self compensating flat balance spring, micrometer regulator, hack mechanism.