From Casio G-Shock, the innovator of tough timekeeping, comes the GGB100 Master of G Mudmaster watch series that has been designed to endure the toughest environments. This watch features a carbon core guard structure case, with grey accents, that allows the internal mechanics of the watch to be protected from shock-induced damage. This watch is mud-resistant with metal buttons that form a tight seal on the case, a dual back cover that consists of a stainless steel panel back and an outer cover made of shock-resistant fine resin embedded with glass fibers, and the bezel has three layers of fine resin with carbon fiber inserts. The Quad Sensor capabilities provide instant access to a compass, altitude/barometer, thermometer, and an accelerometer that keeps track of your step count. Additionally, this watch connects via Bluetooth to a special G-Shock app that helps with the configuration, as well as records altitude data, route information, and step counts. These recordings are used to create an activity log you can use for tracking. Mode switching customization allows you to turn on and off individual modes and their sequence, for a personalized feel. This capable watch is finished with a black resin band. Shock-resistant Includes Bluetooth connected smart link, step tracker, quad sensor, compass, thermometer & altimeter/barometer Double LED light Mud-resistant case & buttons Case Size: 53.1mm black resin case Analog: 3 hands (hour, minute (hand moves every 10 seconds), second) Digital: Hour, minute, second, am/pm, month, date, day 1/100-second stopwatch Countdown timer World time 5 daily alarms Hourly time signal Hand shift feature Button operation tone on/off Regular timekeeping Full auto-calendar (to year 2099) 12/24-hour format Water-resistant up to 200 meters Accuracy: +/-15 seconds per month.