This stop flow is positioned just before the second stage on a regulator, or just before the ADV on a rebreather.

This stop flow is positioned just before the second stage on a regulator, or just before the ADV on a rebreather.

This stop flow is positioned just before the inflator for your drysuit or your wing/BCD. 

This valve allows to cut the gas supply in case of continuous flow. 

It is mandatory to add an over-pressure valve (see accessories) on the 1st stage to avoid a burst hose if 2nd stage is not setup.