Twinlock Winding Crown
Winding crown of Rolex
The screw-down winding crown and the case with screw-down back form the core of the Oyster. Created by Rolex in 1953, the Twinlock system ensures that the screw-down crown is water-resistant thanks to two sealed zones, one inside the tube of the crown, the other inside the winding crown itself. This system is used on all the watches in the Oyster collection that are guaranteed waterproof to 100 metres (330 feet).