Casio G-Shock GRAVITYMASTER Solar Bluetooth Mobile Link Men's Watch GR-B100-1A3 / GR-B100-1A3DR G-SHOCK GRAVITYMASTER has long been the timepiece series at the forefront tough timekeeping. Now these new aviation watch models take this one step further with designs that provide the accuracy and function required during flight. Large hour and minute hands and hour markers improve readability. These models let you schedule up to five flight times, with a seconds unit countdown until the next flight time. The large LCD is designed in the image of a glass cockpit of a passenger aircraft, which provides pilots with a clear view of information. Five side buttons and a front light button help to simplify operation by providing more direct access to functions. These models are the first of the G-SHOCK lineup to feature a large 7 × 33-dot LCD, and an ion plated multi-faceted metal bezel, creating the image of a state-of-the-art aircraft. A bi-color molded band adds a definite touch of fashionable elegance. Connected Engine supports time correction using a time calibration signal and Bluetooth connection. After connection with a smartphone with Bluetooth , you can use the G-SHOCK Connected* app to configure countdown alarm settings, to manage waypoint memory contents, and to manage and store a flight log of distances and travel times of flight missions. To ensure timekeeping accuracy, time information can be obtained from an on-line time server and used to correct the watch's time setting. The app also can be used to configure World Time, timer, alarm, and other settings. In addition to these Phone Linking features, these watches come with high-brightness LED illumination, World Time, stopwatch, and more. Stable operation is ensured by a Tough Solar charging system that incorporates original CASIO energy saving technology. Phone linking Flight Log Function using waypoint memory Auto time adjustment (four times a day) Easy watch setting - World Time for approximately 300 cities - Time swapping - Auto time zone and summer time rule updating - Alarm/Timer settings Phone Finder Battery level indicator (seven levels) Watch Functions Tough Solar Hand shift feature World Time: 39 World Time cities, 39 time zones and UTC, Home Time/World Time swapping 1/1000-second stopwatch Countdown timer: 1/10-second countdown, up to 24 hours Multi-Alarm: 5 alarms with date setting, hourly time signal Super Illuminator (double) illuminates the face and digital display