Brand: Rolex Item name: Datejust 31 Boys Watch Diamond Bezel 10P Diamond Black Shell Item name (English):Datejust Model #: 278383RBR Material: 18K Yellow Gold SS Case material: gold steel Strap material: gold steel Movement: Automatic winding Weight: 97.6 g Case diameter (H): 31 mm (1.22 in) Case diameter (W): 31 mm (1.22 in) Arm circumference (cm): 17.5 cm (6.89 in) Dial: black shell date: January 2022 Accessories: Box details: In-house 3 month Maintenance: Polished Item Description: New model released in 2020. Equipped with the in-house chronometer-certified movement "cal. 2236." This is Rolex's unique high-precision chronometer-certified model. It has cleared the inspection standards twice that of Chronometer. Which is known for its strict inspection standards. Item Condition:. Roulett.