Description: Rolex Datejust 126234 Pre-owned Rolex Datejust 36 ref 126234 (2025). When the Datejust first debuted in 1945, it was introduced exclusively in a 36mm case size, a dimension that would go on to define the model for generations. Even as Rolex expanded the lineup with larger variations over the years, many collectors still view the 36mm Datejust as the purest and most versatile expression of the collection thanks to its balanced proportions and timeless wearability.