Designed and engineered to withstand rough land environments, the Casio G-Shock Mudmaster GGB100 carbon watch protects against damage and deformation due to impact. Case is made of high-rigidity carbon material protects against damage and deformation, while metal button pipes ensure a tighter seal against the external environment A filter further protects against the invasion of mud, for the high level of dust and mud resistance required when in severe environments In addition, the dual back cover consists of a stainless steel panel back and an outer cover made of shock-resistant fine resin embedded with glass fibers Quad Sensor capabilities use compact sensors to pack a compass, altitude/barometer and temperature measurements, along with an accelerometer that keeps track of your steps A G-Shock app simplifies configuration of watch settings and includes a new Mission Function App automatically records altitude data measured by watch and route information acquired by a smartphone's GPS; manually obtained altitude points can be plotted on your route Mineral glass; carbon core