Among all Patek Philippe chronographs Ref. 1506 is surely the rarest and therefore the least well-known. Of an extra- large size for the time with straight lugs decorated by three facets only three examples are known to date; two in pink gold with pink dial and one in yellow gold. Of the three the present watch is the one in the most original condition. An identical watch is illustrated in “Patek Philippe Wristwatches” by Martin Huber and Alan Banbery second edition p. 267.