THE Buoyancy Compensator Device (BCD) is arguably the most important piece of equipment a scuba diver will wear.

The BCD not only allows the diver to rest at the surface but importantly allows the diver to float effortlessly underwater by controlling his buoyancy.

A BCD that is becoming more popular with experienced divers is the Halcyon back-mounted type.

Halcyon are specialists in the cave and cavern-diving market.

This particular BCD can be set up to carry either a single air cylinder or twin cylinders.

The stainless-steel plate or wing has a long, narrow profile that supports the diver's cylinder along his entire length, preventing unnecessary drag and minimising in-water effort.

The adjustable harness allows the diver total control of his buoyancy.

When cave or cavern diving, it is important a diver keeps his body in a horizontal position to avoid stirring up the bottom.

This is also the case when diving inside ship wrecks.

A group of local divers heading to Mexico next month to dive the caves and caverns known as Cenotes will mostly be wearing back-mounted BCDs.