The scuba diving regulator is synonymous with Aqualung. Why? Because we invented it! Every aspect of our technology is geared towards performance and comfort, and we continue to innovate with the best underwater breathing devices on the market.

Learn more about our three key technologies.


ACD, also called Auto Closure Device, is a regulator technology used in the first stage. ACD prevents water and debris from reaching first stage parts or lubrication, maintaining oxygen compatibility and extending life between services.

When the first stage is not connected to a cylinder valve, the ACD keeps the inlet shut to protect the first stage's internal parts from contamination and corrosive water. It preserves the internal lubrication and keeps the inlet filter clean and dry. The Auto Closure Device is both available in Din 300b and Yoke 232b. It is a system patented under US20060157123.

ACD minimum position

ACD maximum position


The OBM, or Over-Balanced Mechanism, is a regulator technology used in the first stage. It is balanced to both depth and tank pressure. Our auto-balanced or over-balanced system gives you the same easy breathing at every point throughout every dive.

While most modern regulators can compensate tank air pressure drops, they can’t balance the variations of the ambient hydrostatic pressure as you descend deeper. The Aqualung Leg3nd’s first stage overcompensates the interstage pressure to lower your breathing effort.


The MBS, also called the Master Breathing System, is a regulator technology used in the second stage. The integrated control of the Venturi effect and inhalation effort means only one adjustment completes both tasks simultaneously.

The Leg3nd MBS allows divers to adjust two essential parameters with an easy turn of the knob. This revolutionary combination allows you to adjust the Venturi effect and inhalation effort simply and simultaneously. A diver can quickly and easily adapt the regulator’s performance to their breathing preferences. With the MBS on minimum position (one full knob rotation), the spring is fully compressed and your inhalation effort is about 3 mbar higher. The risk of free flow is much lower when the Venturi blade restricts the injection outlet. With the MBS on maximum position, the airstream injection is unrestricted and the flow is maximized for unlimited easy breathing.

Discover other Technologies

Discover other Technologies