The Casio G-Shock GM-2100B-4A is a robust analog-digital wristwatch that combines the iconic shock resistance of the G-Shock series with an enhanced metallic aesthetic. This model features a stainless steel bezel with an ion-plated black surface, complemented by a matching black resin strap for a sophisticated yet durable appearance. The watch combines analog hands with a digital display and offers numerous timekeeping functions: world time for 48 cities, a stopwatch with 1/100-second precision, a countdown timer, and five daily alarms. It has automatic calendar correction until 2099 and an LED backlight with afterglow for optimal readability in low light. Built with Casio's shock-resistant technologies, this model is water-resistant up to 200 meters, making it suitable for professional marine activities and surface water sports. The mineral glass dial ensures scratch resistance, while the stainless steel back guarantees long-term durability. The watch measures approximately 49.3 mm in diameter and 12.8 mm in thickness, weighing 72 grams, providing a prominent wrist presence without excessive bulk. It operates with a standard CR2016 battery with an approximate battery life of two years. The GM-2100B-4A retains the core functionality of G-Shock while presenting a refined design that is suitable for both active use and everyday wear. The combination of metallic and resin materials creates a balanced construction that withstands shock impacts while maintaining visual appeal. This model represents a continuation of the G-Shock legacy with improved material quality and refined design elements.