These are downstems, which fit into the Pod, Jar, F4, Orb, mini Tank, middle Tank, and Tank Hookahs. They are all glass construction and are designed to fit into the Fumo Standard Glass Bowl. The only difference in these downstems is that each one is a different length to fit the corresponding Fumo hookah. The downstem consists of an integral diffuser bottom, glass ground joint and a vortex bowl spire. The diffuser end is designed to reduce noise and increase cooling of the smoke. The 3 holes in the vortex spire allows air to be drawn deeper into the tobacco providing a more even tobacco burn and better more complete tobacco utilization. The glass ground joint provides a tight seal between the bowl and the downstem.