The Oyster Perpetual Explorer and Oyster Perpetual Explorer II evolved from Rolex’s deep involvement with exploration. They go where few people venture. The brand was able to test these watches in real life by equipping polar, mountaineering and caving expeditions over many years. Some of the world’s most intrepid explorers, mountaineers and scientists took Explorer and Explorer II watches to places that tested their reliability in the toughest conditions.