The Rolex Explorer II Ref. 226570 in 42mm Oystersteel with a bold black dial is the ultimate tool watch for modern adventurers, purpose-built for those who explore the most extreme environments on Earth, from the depths of caves to the endless daylight of the polar regions . This robust timepiece features a 42mm Oyster case crafted from Rolex’s proprietary Oystersteel, a corrosion-resistant 904L steel alloy that maintains its exceptional finish even in the harshest conditions, paired with a fixed 24-hour graduated steel bezel and the iconic three-link Oyster bracelet that ensures both durability and comfort . The deep black dial provides a striking and highly legible backdrop for the maxi-style hour markers and Mercedes hands, which feature Rolex’s Chromalight display with long-lasting blue luminescence for perfect readability in total darkness . A signature bright orange 24-hour hand sweeps the dial, pointing to the fixed bezel to enable the wearer to easily distinguish day from night—a critical function for spelunkers, volcanologists, and polar explorers . The dial also includes a practical date window at the 3 o’clock position, magnified by the iconic Cyclops lens on the scratch-resistant sapphire crystal . At its heart beats the manufacture Caliber 3285, a COSC-certified Superlative Chronometer automatic movement that delivers a 70-hour power reserve, a Paramagnetic blue Parachrom hairspring for enhanced shock and magnetic resistance, and Rolex’s innovative Chronergy escapement for unparalleled precision and reliability . With 100-meter water resistance, a screw-down Twinlock crown, and a solid, secure Oysterlock clasp featuring an Easylink 5mm comfort extension link, the Explorer II 226570 is engineered to be as resilient as it is functional . Presented in Rolex’s signature green packaging, this iconic timepiece honors the brand’s rich heritage of exploration while offering contemporary adventurers a perfect blend of rugged capability, technical sophistication, and timeless design . Key specifications: 42mm Oystersteel case; black dial with Chromalight display; Caliber 3285 automatic movement; 70-hour power reserve; Oystersteel bracelet; 100m water resistance; fixed 24-hour graduated bezel; sapphire crystal with Cyclops lens.