Basically the BCD allows the diver to inflate or deflate the device of air, allowing the diver to sink or rise when in the water.
There are two popular BCD styles are the jacket style and vest style. Most scuba resorts and organizations rent out jacket style BCDs these days. The video above showcases a jacket style BCD.
The BCD has several functions & features:
- A back-plate and straps to hold the divers air tank
- Straps to hold your gauges and octopuses,
- Newer BCDs have integrated weight systems – allowing divers to place their weights inside their BCD, instead of using a weight belt.
- A low pressure direct feed that transports gas from diving cylinder and diving regulator to the BC.
- A vent valve that allows gas to escape from the bladders of the BC.
- An inflation valve that allows gas from the direct feed into the bladders of the BC.
- An over pressurization valve that automatically vents the bladders if the diver over inflates the BC by ascending or by injecting too much gas.
- A harness that the diver wears with straps around the torso and over the shoulders
- D rings or other anchor points, for clipping on other equipment such as torches, strobes, reels, cameras and stage cylinders