Aquatec RG-3100S Second Stage with 75cm Hose

Second stage ? Mouthpiece you breathe from. Also called a demand valve because it gives you air when you demand it (inhale) at the exact pressure you need for breathing comfortably.
Diving Regulator Adjustable Second Stage, Dive Regulator Downstream Valve Type, Regulator alternate air source, Saft second stage, Octopus

Scuba Gear Technical Information:
Type: Pneumatically balanced design gives consistent gas pressure for easy inhalation
Intermediate pressure: 150 PSI.
Inhalation effort: 1.2-1.4 CIW (Column inches of Water).
Exhalation efferot: 1.1 CIW.
Flow rate: 30+SCFM (Air supply: 3000PSI).
Pneumatically balanced design gives consistent gas pressure for easy inhalation
Venturi assist directs airflow from the valve directly to the mouthpiece producing smooth inhalation
Easy grip dive/pre-dive switch avoids free at surface and is easy to use with gloves
Orthdontic mouthpiece reduces jaw fatigue on long dives
Adjustable design helps diver fine tune cracking pressure so breathing resistance matches diver personal preference.
Deflection ring works to maximize performance while deterring free flow
Available as a standard right-hand regulator
Second stage adjustment knob: Fine-tunes inhalation effort
Weight: 237g (0.52lb)
Faceplate Color: Green, Blue, Purple, Orange, Red, Yellow, Red