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:      - 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
- 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)
- 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