Bubblers serve two purposes: cleaning the HHO gas and acting as a safety barrier. When HHO gas is produced from a dry cell, some water vapor is produced as well. This water vapor can carry tiny particles of electrolyte which can cause harmful corrosion. As the HHO bubbles rise up the water column inside the bubbler they are "scrubbed" of any electrolyte particles that have been attached to the water vapor. The result is much cleaner HHO gas. In the event of a flashback, the bubbler acts as a safety barrier. If a flame reaches the bubbler and ignites the HHO that has built up at the top, the water column prevents the HHO from going to the dry cell because the flame cannot go from bubble to bubble. - Tank Comes with three (3) 3/8". Black nylon barbed fittings and 9 mm inside PVC pipe fitting