Underwater breathing gear, also known as SCUBA (Self-Contained Underwater Breathing Apparatus), is a type of equipment used by divers to breathe underwater. It consists of a tank of compressed air, a regulator, and a face mask or full-face mask. The air tank is worn on the back and supplies air to the regulator, which is connected to the face mask. The face mask allows the diver to see clearly underwater and breathe normally. SCUBA is used for recreational and professional diving, and is essential for deep sea exploration.