Master of G series watches are invariably amongst the largest G-Shock designs Casio produces, usually suited for those with larger wrists. They are almost always named with a "man" suffix after the initial Frogman model which itself was named for scuba divers. Three models, the Mudman, Gaussman, Raysman and Rangeman all feature a thick rubber outer layer that surrounds the buttons and case completely, ensuring that they offer mud-resistance.