The Casio G-Shock Gravitymaster GR-B100-1A4 is a high-performance aviation timepiece designed for pilots and aviation enthusiasts. Part of the Gravitymaster series, this model features a bold black and orange color scheme with a distinctive two-tone layered resin band. This watch is powered by Casio's Tough Solar technology, ensuring reliable operation without the need for battery replacements. It also features Bluetooth Smartphone Link for automatic time adjustment, flight log recording, and easy watch setting via the G-SHOCK Connected app. The large case measures 53.8mm in diameter and is built with a shock-resistant resin and stainless steel structure. The watch features a large, high-resolution STN LCD display inspired by the glass cockpit of modern aircraft, providing clear visibility of flight data. Key functions include a flight log memory, world time (39 cities), a 1/1000-second stopwatch, countdown timer, and 5 multi-function alarms. It is protected by Mineral Glass and illuminated by a double LED light (Super Illuminator). With a water resistance rating of 200 meters (20 Bar), it is built to withstand the rigors of flight and outdoor activities.