Casio G-SHOCK GR-B300EC-1ADR GRAVITYMASTER WatchMASTER OF G AIR GRAVITYMASTER GR B300EC 1ADR Whatever youre doing, wherever you are the G SHOCK Master of G line has your back. Based on GRAVITYMASTER, MUDMASTER, and MUDMAN models that deliver peak performance in punishing conditions in the air and on land, this line features a black watch case symbolizing toughness, with accents in vivid emergency colors that capture the world of professionals involved in rescue efforts and other critical missions.