An update to the CHRONOGRAPH CHALLENGE TIMER, which debuted in 1973 as Citizen's first watch with a full-scale chronograph function. An icon model that has been nicknamed "Tsuno Chrono" because the push button located on the 12 o'clock side of the case looks like a horn. Unlike ordinary watches, it has an exquisite design that harmonizes the soft case shape and the sharp bezel, with a unique balance that deviates from theory. With a case size of 38.0mm, it fits comfortably on your wrist. / Caliber: 0510 / Accuracy: ±20 seconds per month / Second hand stop function / Quick date correction function / 1/1 second chronograph (12 hour meter) / Battery life of about 2 years / Battery used 280-44 / 5 ATM water resistance / Luminous (needle + index)