An update of the "Chronograph Challenge Timer," introduced in 1973 as Citizen's first watch with a full-fledged chronograph function. This iconic model has been nicknamed "horn chrono" because the push button placed at 12 o'clock on the case looks like an antler. Unlike ordinary watches, the balance that deviates from the theory makes it stand out for its individuality, and the soft case shape and sharp bezel are in harmony with each other to create an exquisite design. The case size is 38.0mm, which fits comfortably on the wrist. /Caliber: 0510 / Accuracy: ±20 seconds per month / Second hand stop function / Date correction function / 1/1 second chronograph (12-hour counter) / Battery life: approx. 2 years / Battery 280-44 / Water-resistant to 5 atm / Luminescent (hands + indices)