The Oyster Perpetual's Oyster case, a classic feature of Rolex, provides a water-resistant function to a depth of 100 meters. The case is crafted from a solid block of robust Oystersteel, resistant to corrosion. Special tools are used to tightly screw down the finely grooved case back, ensuring the case's seal. The Twinlock double waterproofness system is an essential part of the water-resistant structure, securely fastened to the case. This waterproof Oyster case provides the best protection for Rolex movements, offering excellent water and dust resistance.