A BCD is a piece of scuba diving equipment that helps the diver control their buoyancy underwater. It is typically worn on the diver's back and can be inflated or deflated to adjust the diver's buoyancy.

The recommended maximum depth for recreational scuba diving is 30 meters (98 feet). This depth limit is based on the fact that the pressure of the water increases with depth, and at depths greater than 30 meters, the risk of decompression sickness (DCS) increases significantly.

A snorkel is a piece of snorkeling equipment that allows the snorkeler to breathe underwater. It is typically a long, hollow tube that is held in the snorkeler's mouth and extends above the water's surface.

The recommended minimum age for scuba diving is 12 years old. This age limit is based on the fact that younger children may not have the physical and mental maturity to safely participate in scuba diving.

A scuba diving mask is a piece of scuba diving equipment that allows the diver to see clearly underwater. It is typically made of a clear material, such as glass or plastic, and is worn over the diver's eyes.

A scuba diving regulator is a piece of scuba diving equipment that provides air for the diver to breathe underwater. It is typically attached to the diver's scuba tank and consists of a mouthpiece, a demand valve, and a hose.

A scuba diving wetsuit is a piece of scuba diving equipment that helps to protect the diver from cold water. It is typically made of a neoprene material, which is a synthetic rubber that is known for its insulating properties.

A scuba diving dive computer is a piece of scuba diving equipment that monitors the diver's depth, time, and air pressure underwater. This information is used to calculate the diver's decompression status and to warn the diver of potential decompression sickness (DCS) risks.

A scuba diving underwater propulsion vehicle (UPV) is a piece of scuba diving equipment that propels the diver through the water underwater. It is typically powered by an electric motor and can be used to travel long distances underwater.

A scuba diving underwater camera is a piece of scuba diving equipment that is used to take photos and videos underwater. It is typically a waterproof camera that is mounted on the diver's scuba gear.

A scuba diving underwater light is a piece of scuba diving equipment that is used to illuminate the underwater environment. It is typically a waterproof flashlight that is mounted on the diver's scuba gear.

A scuba diving underwater knife is a piece of scuba diving equipment that is used to cut through underwater obstacles. It is typically a sharp, stainless steel knife that is mounted on the diver's scuba gear.

A scuba diving underwater compass is a piece of scuba diving equipment that is used to navigate underwater. It is typically a waterproof compass that is mounted on the diver's scuba gear.

A scuba diving underwater slate is a piece of scuba diving equipment that is used to write notes underwater. It is typically a waterproof slate that is mounted on the diver's scuba gear.

A scuba diving underwater signal device is a piece of scuba diving equipment that is used to signal for help underwater. It is typically a whistle or an air horn that is mounted on the diver's scuba gear.