Accompanied by Patek Philippe Extract from the Archives confirming production of the present watch with gold bracelet in 1973 and its subsequent sale on 28 September 1973.
Reference 3587/2, the largest wristwatch ever made by Patek Philippe, was launched in 1970 and fitted with an electronic movement, introduced into the market at the Basle Fair in April 1970.
The Beta-21/Beta-22 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.
The Beta-21 is described and illustrated in Patek Philippe Wristwatches by Martin Huber & Alan Banbery, second edition, p. 332, pl. 486 & 487.