A good BC does more than just keep you off the bottom. It also allows you to maintain depth without kicking, and lets you swim in a horizontal, rather than angled, position. Less kicking means less energy required, and less air consumed. And swimming horizontally helps you stay as streamlined as possible – which again consumes less energy … and less air. So a good BC, used properly, can literally mean the difference between a 20-minute dive and a one-hour dive.

There’s another benefit; when the diver gets back to the surface, the BC can be inflated to keep the diver relaxed and afloat while working back to the boat or the shore. And the BC can assist at the surface in carrying objects such as those cool treasures you’re going to find while diving. With this in mind, you will often hear discussions of how much “lift” a particular BC has. This is a reference to how much weight it can support when fully inflated.