Oyster means an integrated case and screw-in case and crown. When we talk about Oyster case, we want it distinguished from other welding lug and pressed-in case, to put it simply, the Oyster case is made of stainless steel that is made through a modeling and no more other processing.
The history of Rolex Oyster could date back to 1926 when Rolex invented the first Oyster case and filed patent for it. As the first Oyster case it took the lead back then and so far as to now it is the most recognizable watch. It was the result of Rolex watch-making skills and professional knowledge. So today we have a different and distinguished watch-the refreshing Rolex Oyster Perpetual Lady watch and the official number is 176200-70130.
Small as 31 mm of the case diameter, Perpetual Lady has an arc bezel, looks delicate and a perfect size for ladies’ wrist. The simple dial that only has three hands and blue sapphire mirror presents a clear reading. Oyster case is the key point in the watch and crucial foundation for the watch, so the 904L stainless steel, which is widely employed in high-tech fields, aviation, chemical parts, etc, due to its amazing performance in anti-corrosion, is applied in making the Oyster case, the double clasps on the crown is easy to manipulate and the double clasps is amazingly good in water resist, so it can reaches 100 meters depth under the water. You will also see other Oyster features on this Perpetual Lady watches, such as the Oyster bracelet. This Oyster bracelet consists of three lines of wide and flat knots on the strap, which is extremely hard. This kind of bracelet is common on other Oyster case. Looking carefully at the buckle, a very small Rolex crown is branded on it.