ref.570
Yellow, Antimagnetic

A very fine and extremely rare 18k yellow gold manual-winding wristwatch ref.570 with antimagnetic movement.
With Patek Philippe Extract from the Archives

The large Calatrava model ref.570 was introduced into the market in 1938, featuring either subsidiary or sweep centre seconds. The present watch is from the first series made with subsidiary seconds but with the extremely unusual particularity of a 27-AM 400 anti-magnetic movement, normally reserved for Patek Philippe's "Amagnetic" watches such as references 2570/1, 3410, 3417 etc. The amagnetic calibre 27-AM 400 was launched in 1960 and is an improved version of the 1958 calibre 12'''400, fitted now with a Gyromax balance and free sprung self-compensation Breguet overcoil hairspring.

"Amagnetic" watches were designed for use in areas of high electro-magnetic fields such as in laboratories or electro-engineering. It can therefore be assumed that the original owner of this watch ordered it purposely with an amagnetic movement, as confirmed by the Extract from the Archives.