The hose port opening connects directly to the hose port and does not connect to any part of the main stem or down stem. And everything is with in Jakarta.

It is used for clearing out stagnate smoke. By blowing into the hose, smoke is pushed back this in Jakarta into the vase and through the release valve port opening up to the release valve. The air pushing up through the release valve causes a metal ball bearing to rise up, which allows the smoke to be released. The ball bearing is in the check valve to keep the hookah airtight when smoke is being inhaled.