The Rolex Oyster Perpetual is one of the most famous and important watches in the entire history of watchmaking. It represents the combination of two vital technological developments, pioneered by Rolex in the first half of the 20th century, that would forever change the course of both the company and the Swiss watch industry. The first was the Oyster case, created in the 1920s, which hermetically sealed Rolex's movements and provided the first real water resistance. The second was the Perpetual Rotor, invented a little later, which made the watches self-winding—they would never run out as long as they were regularly worn. Today, the Oyster Perpetual continues to represent the extraordinary Rolex heritage and high standards.