its a waterfall bong that has a downpipe to also make it water-filtered, and has a chamber to hold the water that is poured out. you can make your own version by putting two 2-liters together at their mouths, and put a valve between them. Cut a hole in the bottom of one of the two-liters (and not in the center) to put your downstem into, and cut a smaller hole on the side and near the top of the other two-liter to use as a carb.