The Rolex Explorer II reference 1655, often recognized by its distinctive orange 24-hour hand, was introduced as a tool watch for speleologists and polar explorers. It offered enhanced legibility in low-light conditions and a fixed 24-hour bezel to distinguish between AM and PM in environments where day and night cycles are obscured. This model stands apart from its GMT-Master sibling by focusing on a specific utility rather than multiple time zones, making it a specialized instrument within the Rolex professional line. This reference features a 39 mm stainless steel case, housing the automatic Caliber 1575 movement. The movement provides a power reserve of approximately 42 hours. A robust acrylic crystal protects the black dial, which is characterized by its luminous hour markers and the prominent orange 24-hour hand. The watch is water-resistant to 100 meters, suitable for its intended robust use. Collectors value the 1655 for its unique aesthetic and its position as the original Explorer II. Its fixed bezel and distinctive hand set differentiate it from later Explorer II iterations and other Rolex sports models. The reference appeals to those who appreciate purpose-built watches and the early design language of Rolex's professional series, representing a specific chapter in the brand's history.