The buoyancy compensator is the backbone of the SCUBA diving system. One of the most important pieces of gear a diver will ever own, it is imperative that no compromises are made in choosing the right one for you. A well-engineered BC allows the diver to float comfortably on the surface in a face up position and facilitates precise, easy changes in underwater body position. Equally important, a good BC will conform securely to the diver's body to minimize underwater drag and swimming effort, and will provide a comfortable, nonrestrictive fit around the shoulders and at the waist.