By-pass valve and by-pass arm
The by-pass valve is located in the regulator block that is activated when the diver presses the by-pass arm.
The by-pass arm is located on the regulator block.
When the by-pass arm is pushed backwards, this presses in the end pin of the by-pass valve whereupon the valve opens and releases gas directly into the breathing circuit through a nozzle in the regulator block.
By-pass valve.
By-passes should be avoided near acoustically sensitive objects as they reduce the acoustic signature.