The Longines Ultra-Chron L2.836.4.52.6 is a modern reinterpretation of the 1968 Ultra-Chron Diver, featuring a 43mm stainless steel case and a black dial with Swiss Super-LumiNova® for enhanced legibility. Powered by the high-frequency Calibre L836 automatic movement, it operates at 36,000 vibrations per hour and offers a 52-hour power reserve. The watch includes a unidirectional rotating bezel, a screw-in crown, and is water-resistant up to 30 bar (300 meters). It is fitted with a stainless steel bracelet secured by a triple safety folding clasp with push-piece opening mechanism. Reference number: L2.836.4.52.6.