The new Rolex Explorer in steel with an entirely luminescent display for enhanced legibility. The model’s characteristic 6 and 9 numerals are now filled with a luminescent material emitting a long-lasting blue glow, like its hour markers and hands
This is a 1964 Rolex Explorer advertisement. It shows how watch companies take the idea of exploration, such as the issues of keeping time consistently in adverse conditions. Here the Rolex is capable of surviving the climb to the top of the Matterhorn.