The CC/OC valve allows easily and fast to switch between the close
circuit (the CC mode) and the open circuit (OC mode) by one
hand. It is operated by rotating the knob on the front of
the SM BOV.
When the SM BOV is switched to the CC mode – the
breathing loop is open via the mouthpiece and allows
the diver to breathe on the rebreather closed circuit.
When the SM BOV is switched to the OC mode – the
breathing loop is closed and allows the diver to
breathe on open circuit via the 2nd stage regulator. In
this position no water can enter the breathing loop even
when the BOV is out of the diver’s mouth and
One-way directional valves (mushroom valves) provide
and ensure the correct breathing gas circulation in the
breathing loop in the correct direction from left to right, from
the inhalation counterlung to the exhalation counterlung.
The SM BOV 2nd stage regulator is supplied with diluent via the
LP hose running parallel to the breathing hoses and connected
to the Diluent MAV via the Shut-Off Valve.