So-called ?Rigid Hooded? watches in such good un-restored condition are rarely found in the combination of steel and pink gold. The dial is exceptional because the hour numerals and the minute track are in relief. The caliber 9 3/4??? Ref. 620 was created in 1936 and was in regular production between 1940 and 1951. This watch is illustrated in ?Rolex Collecting Wristwatches? by Osvaldo Patrizzi 2001 Edition p. 161.