Rolex Datejust 78278

Reference 78278 is the solid 18k yellow gold, fluted-bezel model from the 31mm ‘Mid-Size’ Datejust 78xxx series, produced from approximately 1999 to 2006. As the direct successor to the Ref. 68278, it is historically significant for introducing the upgraded Rolex Caliber 2235 to this model line. This 31-jewel COSC-certified chronometer offered improved architecture and a 48-hour power reserve. The technical specification denotes a 31mm case with a fluted bezel (27 code) in 18k yellow gold (8 suffix), fitted with a sapphire crystal. It represents the modern iteration of the classic solid gold Mid-Size Datejust.