Casio GA2100-1A1 is a moderately sized Casio G-Shock watch. Casio GA2100-1A1 men's G-Shock watch has a full array of features that inclue the following: shock resistant, 200 meter water resistant, auto LED light with afterglow, world time, 5 daily alarms, hourly time signal, countdown timer with 1 second measuring unit, full auto-calendar pre-programmed till year 2099, 12/24 hour display format. Casio GA2100-1A1 is backed by Casio's one year factory warranty.