The Mark V is a type of deep-sea diving suit designed for underwater exploration. It features a heavy metal helmet and a weighted suit, allowing divers to work at great depths while being protected from water pressure. The suit is equipped with a communication system, enabling divers to stay in contact with surface support teams. Originally developed in the early 20th century, the Mark V became widely used by the U.S. Navy and commercial divers. Its design has influenced modern diving equipment, and it remains a symbol of underwater exploration, often associated with the history of diving technology and marine research.