 The ability to remove tanks and push them in front allows the diver to pass through very small passages and holes when penetration diving – being limited only by the bulk of their bodies and diving suits.Streamlining for reduced drag while swimming is not always achieved.Increased accessibility to regulator first-stages and cylinder valves improves efficiency and speed of critical cylinder shut-down procedures, allows immediate gas-loss identification and provides the diver with quick access to alternative contingency procedures, such as swapping regulators between cylinders, manual operation of a cylinder valve to control gas flow through a regulator which is free-flowing, or to allow breathing directly from the tank valve.