Ref. 2526First launched by Patek Philippe in 1953,this is the first self-winding wristwatchmodel ever made by the compan y, with thecalibre 12'''-600 AT, bearing the serialnumber 760?000.It would appear that Patek Philippeproduced the Ref. 2526 in 580 e xamples,mostly with enamel dial.? 20 examples in platinum.? 30 examples in white gold.? 50 examples in pink gold.? 480 examples in yellow gold.The Ref. 2526 is a most appealing wrist-watchand highly sought after by collector s.There have been four generations of thismodel which have evolved as follows:? 1st generation:domed screw back, synthetic beige enameldial with applied indexe s. The enamel isf l a red around the holes which hold theindexe s, the central hands and thesubsidiary seconds hand.? 2nd generation:domed screw back, synthetic beige enameldial with applied inde xes. The indexes areinlaid in the enamel surface; the enamel isflared around the holes which hold thecentral hands and the subsidiary secondshand. In this particular series, only veryfew examples were made with black dialand even fewer with Breguet numerals.? 3rd generation:identical to the 2nd generation but withpractically flat screw back. Very fewexamples of this series were producedwith black dial, and only one with blackdial and Breguet numerals is known t odate.? 4th generation:p ractically flat screw back, synthetic beigeenamel dial with applied index e s. Thei n d exes are luminescent and inlaid in theenamel surface; the enamel is flared ar o u n dthe holes which hold the central hands andthe subsidiary seconds hand.