The Explorer II is equipped with an additional 24-hour display; a dedicated hand circles the dial in 24 hours rather than the usual 12, pointing to a fixed bezel with 24 hour graduations. This function enables the wearer to distinguish the hours of the day from the hours of the night, an essential feature for those who venture into environments where darkness reigns supreme – such as in the depths of caves, or where the sun never sets – like the polar regions in summer.

The Explorer II features a date display, an additional orange 24-hour hand and a fixed bezel with 24-hour graduations, enabling day to be distinguished from night. It became the watch of choice for speleologists, volcanologists and polar explorers. Its hour markers and hands feature a highly-legible Chromalight display with long-lasting blue luminescence.

Rolex uses Oystersteel for its steel watch cases. Specially developed by the brand, Oystersteel belongs to the 904L steel family, alloys most commonly used in high-technology and in the aerospace and chemical industries, where maximum resistance to corrosion is essential. Oystersteel is extremely resistant, offers an exceptional finish once polished and maintains its beauty even in the harshest environments.