The characteristically shaped middle case is crafted from a 904L steel. The fluted case back is hermetically screwed down. The dial for the 39mm Rolex Oyster Perpetual is stunning dark rhodium sunray finished one, with small blue accents and white gold hour markers and hands. Inside, you'll find Rolex caliber 3132, an in-house developed and manufactured reliable movement that has been chronometer certified by COSC with 48 hours power reserve. The Oyster Perpetual is paired with a solid-link 904L steel, rather elegant Oyster bracelet.