An entirely new automatic movement has been developed for this steel chronograph model of the celebrated Royal Oak. With a total height of 5.50 mm, this movement is among the smallest in its category. Calibre 2385, 21,600 vibrations per hour, 37 rubies, 40-hour power reserve. Screw-down crown, disconnectable chronograph push-pieces, water-resistant to 50 m, solid steel bracelet with adjustable folding clasp.