Essential for all water pipes. Without it, you basically just have a piece of glass.
Glass-on-Glass downstem with a showerhead perc on the tip. Just the tip. 6" in length, fits into a 14 mm joint and fits a 14 mm joint. Note: be sure to measure the length from fitting to bottom of waterpipe to ensure there's no overhang.
Waterpipe will not function properly if not flush.