This exceptional waterproof design was patented in 1926 and gave Rolex watches their reputation. It was the beginning of the Rolex success story. The Twinlock system, introduced in 1953, guarantees that the screw-down winding crown is perfectly water-resistant thanks to two sealed zones, one inside the tube, the other inside the crown.
”...It was designed to offer increased water-resistance for the Submariner, Sea-Dweller and Rolex Deepsea divers' watches, guaranteed waterproof to depths of 300 metres.”
This principle is used on all the watches in the Oyster collection that are guaranteed waterproof to 100 metres. Introduced in 1970, the Triplock system has a third sealed zone inside the tube of the crown.
It was designed to offer increased water-resistance for the Submariner, Sea-Dweller and Rolex Deepsea divers' watches, guaranteed waterproof to depths of 300 metres. Also, the crown not only hermetically seals the case – it also provides access to the watch's key functions.