Chronograph antimagnetic with triple date Produced from the mid 40s to the early 60s in few examples in 18K yellow or pink gold and very few in stainless steel with different design of dial and shape of hands with 4 different references: - in the mid 40s Ref 4767. - from 1948 to 1951 Ref 5036. - from 1951 to 1955 Ref 6036 so-called by collectors "Billy watch" (world ski champion in the 60s). This reference was produced in 170 examples in yellow gold 144 examples in pink gold and very few in stainless steel. - from 1958 to 1962 Ref 6236. The main difference between this one and the three other references consists in the three body case as opposed to two body. A watch Ref. 5036 is published in Collezionare Orologi da Poiso Rolex Edition 1998 by Osvaldo Patrizzi Guido Mondani Editore Genova pp. 317 and 380.