It might seem counterintuitive that you would equip a scuba diver with a life vest, but there would be a genuine benefit to the use of the Revival Vest, especially for amateur underwater explorers and professionals taking risks.
The compact aquatic accessory is fastened around the chest and shoulders of the wearer so that it's as little of a physical hindrance as possible. In its passive state, the equipment remains deflated so that one can descend below the surface of the ocean just as easily as he usually would.
Worn with James McNab's gear is a strap around the torso that monitors the signs of respiration. This data is sent to the Revival Vest if it seems that the wearer might be losing consciousness. If this is the case, the safety device will inflate with carbon dioxide around the user's neck and head and send him up to air for resuscitation.