The first inhalation under water is the start of a new adventure. The revolutionary combination of Venturi effect and inhalation effort adjustment is natural and intuitive. Aqua Lung's Master Breathing System allows divers to control both in one simple rotation. All depths, all conditions, all dives - MBS will adapt.

First Stage

• When the first stage is not connected to a cylinder valve, the Auto Closure Device (ACD) keeps the inlet shut to protect the first stage internal parts from contamination and corrosive water.
  • Preserves the internal lubrication.
  • Keeps the inlet filter clean and dry.
  • Safer for elevated percentages of oxygen.
• Exceptional cold-water performance is achieved by modernizing Aqua Lung's three anti-freeze properties:
  1. Where there's no moisture, there's no ice: The LEG3ND's integrated dry chamber keeps inner components clean and dry by isolating them from the outside environment.
  2. Deep ribs create a large heat exchange surface area that helps to prevent ice forming on the mechanism (+30% vs Glacia / +70% vs Legend 2).
  3. The new overmolded cap delays ice forming over the external diaphragm.
• Auto-Balanced (also known as Over-Balanced).
• Progressive increase of the working pressure to maintain optimum breathing efforts: Depending on the diver's depth, the working pressure of the first stage is automatically elevated to counteract the increased breathing air density.
• Ergonomically shaped DIN and YOKE screws made of a bi-material 'Soft Grip' surface provide a better hold when installing or removing the first stage ─ especially with cold hands.
• Channeled YOKE screw to prevent water retention.
• Specialized ACD Dust cap attached to the regulator body to protect the inlet fitting and the ACD system from impacts or damage.
• Perfectly positioned HP and MP ports provide optimal hose routing.

Second Stage

• New front cover opening channels allow water to flow sideways over the diaphragm.
  • Radial openings to prevent freeflows when diving in stronger currents.
  • Openings widened to reduce peak inspiratory flow by an impressive 20%.
• New overmolded exhaust cover made of elastomer with a 'soft touch' effect.
• Overmolded air purge.
  • Wide surface area makes regulator purging easier.
  • Purge depth controller optimizes air flow with minimal effort.
• Patented Comfobite mouthpiece reduces jaw fatigue and secures the second stage more comfortably.
• Detachable and reusable mouthpiece clamp allows a quick and simple tool-free mouthpiece change without plastic waste.
• The enlarged heat exchanger helps to prevent freezing of the second stage mechanism.
• Air channel deflector.
  • Directs the air flow evenly during the inhalation phase.
  • Streamlined bi-material deflector lowers the exhalation effort.
• Flexible and lightweight Aqua Flex hose with dual protectors.