The present invention includes an in-line device that improves safety and ease of use associated with a scuba diving buoyancy compensation device (BCD). Specifically, a rotational coupling and associated valves are provided to assist in closing the air passageway without physically disconnecting the air hose from the BCD for a diver in case of an emergency and may be utilized together with or independently from currently commercially available air hose configurations and is described as an improved buoyancy compensator coupling device (BCCD).