With Patek Philippe Extract from the Archives confirming production of the present amagnetic watch in 1964 and its subsequent sale on 21 February 1964. Furthermore delivered with Patek Philippe fitted presentation box.
Fresh to the market this ref. 2509 is believed to be one of only seven examples of this model with amagnetic movement to appear in public to date.
The particularity of the present reference 2509 is the highly unusual use of a 27-AM 400 antimagnetic movement, normally reserved for Patek Philippe's "Amagnetic" watches such as references 2570/1 and 3460, amongst others. 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 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 both the Certificate of Origin and the Extract from the Archives.
Reference 2509 was launched in 1950 and fitted with the regular calibre 12'''400. Mainly available in gold, the model is distinguished by its sporty design and the water-resistant-type case with screw back.