First Stage:

The balanced diaphragm first stage, by the nature of its design, is environmentally sealed and provides superior, consistent performance
Available in yoke (3300 psi / 232 bar max) or din (4350 psi / 300 bar max)
The T-shape of the first stage optimizes the location of the 4 MP ports and 2 HP ports
2 HP ports and 4 MP ports are angled for optimum hose configuration
Uses parts that are common to other Aqua Lung models for easier servicing
Compatible with EAN 40 new, out of the box
Auto Closure Device (ACD) - keeps corrosive water out of the first stage inlet by automatically closing as the Legend is removed from the cylinder valve
This prevents internal lubrication from washing away
Safer for elevated percentages of oxygen
Balanced, diaphragm design results in excellent performance at depth
Available in your choice of yoke or DIN connectors
Compatible with up to 40% O2 right out of the box
Second Stage:

Pneumatically-balanced second stage results in smooth, easy breathing
The easy-to-grip venturi lever prevents unwanted freeflow at the surface while giving a performance boost at depth
Equipped with Aqua Lung’s patented Comfobite™ mouthpiece along with a reusable mouthpiece clamp
A heat exchanger (patented) which surrounds the valve mechanism, dissipates the cold caused by gas expansion while drawing in the warmth of the ambient water
Supreme Version:

The Supreme cold water version is resistant to freezing when diving in waters colder than 50°F / 10°C
An environmental dry system keeps water out of the main spring chamber thus preventing ice buildup and keeping silt and contamination out
Comes with a lip shield to keep lips warm
Specially adjusted to resist freezing