The downpipe or stem is the connecting part between the body of the bong and the bowl. Sometimes the bowl is already combined with the downpipe.

The downpipe reaches down below the water surface. A popular type of downpipe is the diffuser downpipe: With his many little holes on the bottom this diffuser increases the surface of the smoke bubbles by multiplying them.

Some accessories for the bong are vital some are mere ornamental or for tuning purposes.

Here's an overview over a bunch of devices completing or supporting your bong.