The Casio G-Shock GA-2100-1A3 is a robust men's watch featuring a resin case and strap, designed for durability and reliability. It combines analog and digital displays with a black dial and neon accents, powered by a precise quartz movement (Caliber 5611). The watch includes a mineral crystal for scratch resistance, 200 m water resistance suitable for professional marine activities, and shock resistance for demanding environments. Key functions encompass world time, a 1/100 second stopwatch, countdown timer, five daily alarms, hourly time signal, and luminous hands with Neobrite for low-light visibility. Additional features are a full auto calendar displaying month, day, and date, hand shift to prevent obstruction, button operation tone on/off, and a screwed case back with buckle clasp. Dimensions are approximately 48.5 mm in length, 45.4 mm in width, 11.8 mm in thickness, with a lug width of 16.0 mm, ensuring a comfortable fit for everyday wear.