Scuba diving is a mode of underwater diving where divers use a Self-Contained Underwater Breathing Apparatus (SCUBA), which is equipment completely independent of a surface breathing gas supply. This allows divers to breathe underwater and explore marine environments for extended periods, unlike freediving where divers hold their breath.Scuba divers carry their own source of breathing gas (typically compressed air in a cylinder), supplied through a diving regulator to the diver at ambient pressure. Other essential gear includes a buoyancy compensator (BCD), mask, fins, and a wetsuit. Scuba diving can be enjoyed recreationally for leisure and exploring marine life and coral reefs .