Scuba diving is a mode of underwater diving whereby divers use breathing equipment that is completely independent of a surface air supply, and therefore has a limited but variable endurance.The name “scuba”, an acronym for “Self-Contained Underwater Breathing Apparatus”,A scuba diver primarily moves underwater by using fins attached to the feet.Other equipment needed for scuba diving includes a mask to improve underwater vision,  exposure protection by means of a diving suit, ballast weights to overcome excess buoyancy, equipment to control buoyancy, and equipment related to the specific circumstances and purpose of the dive, which may include a snorkel when swimming on the surface,  a cutting tool to manage entanglement, lights, a dive computer to monitor decompression status, and signalling devices.