One of Patek's greatest complications, the 3970 perpetual calendar chronograph replaced the legendary 2499. This 3rd series example in beautiful 18ct rose gold features the sought after exhibition sapphire crystal case back (screwed-down for water resistance) is a true collectors set, complete with its original Patek box, certificate, solid gold case-back, stylus and correct rose gold Stern pin-buckle (deployant was introduced on the next generation). Rarer in rose gold than the more commonly seen yellow, this is one of Patek's most beautifully refined grand complications, and is currently superb value for money with prices sure to rise.