Patek Philippe’s references 738 and 739 silver deck chronometers were introduced in the late 1930s, however it is interesting to note some movements were made earlier and later encased such as the present watch. The typical construction consisted for these precision timepieces featured an oversized case measuring between 59mm to 62mm diameter, and with a caliber 19”, 21” and 22” movement depending on the case size. The cases were manufactured in silver and stamped with the FFBA (Fédération Fabricants De Boîtes) Swiss silver hallmark. The dials typically carried the movement number enabling ease in check in the Bulletin certificates, and the watch would have originally been issued with a wooden deck box. These deck chronometers were produced in four series:
• 738-open face chronometer with subsidiary dial
• 738-1-open face chronometer with up/down indicator and subsidiary seconds dial with vertical orientation
• 738-2-open face chronometer with up/down indicator and subsidiary seconds dial with a horizontal orientation
• 739-open face chronometer with subsidiary dial, renamed reference 738, like the present watch
These Stern Frères dials were made in metal, silvered or enamel.

The present watch with a S. Graber SA case is in lovely original condition and a fine example of these important precision timekeeping watches.