Known as “Grande Ellipse” or “Elletrico”, reference 3603 was in production from 1973 until 1982 and is together with references 3587 and 3597 amongst the largest rectangular wristwatches ever made by Patek Philippe. Available in either yellow or white gold with Ateliers Réunis cases, the dials were made by Stern Frères from a massive 18K gold plate and were available in either blue, gilt, browned or silvered finishes.
Reference 3603-2 such as the present watch is the designation for watches with the “tubogaz” type solid 18K gold bracelet, the 3603 had a leather strap and the 3603-1 was fitted with a “oyster” style bracelet.
The Beta-21 calibre was developed by a consortium of watch companies, including Patek Philippe, at the Swiss Electronic Research centre or CEH (Centre Electronique Horloger) in Neuchâtel. It was the first quartz movement for wristwatches with analogue display.