Highly desirable gents Patek Philippe Perpetual Calendar Chronograph (third series) in 18K rose gold, Ref# 3970ER. On original reptile strap with 18K rose gold deployant buckle, sapphire caseback, case diameter 36.5mm. Manually wound movement, chronograph functions, 30 minute counter, perpetual calendar, day, date, month, sub seconds, 24Hr display and leap years. Silver dial with day, date, month, leap year, moon phases with am/pm indicator and sub-seconds. Box, pusher, and papers dated September 2004. Comes with additional solid caseback. Superb condition.