Electronic watch powered by battery and regulated by quartz crystal. Stopwatch. Alarm.
Large rectangular case in the upper part has a digital display with multiple functions: time, date, stopwatch, alarm with adjustable tone (10 different) and the numerical game. In the bottom is a calculator. Laterally are four buttons for performing the above functions.
Casio CA 901 is a model with calculator and a game that was launched in 1982. The cover labeled S-100 does not belong to this watch, but to the model Jogging, which went into production in 1983.