Top, the idea is the same as a traditional calabash. There is a larger second chamber that allows the smoke to cool a bit before entering your mouth. The "Reverse" part comes in because the smoke cools inside the shank rather then beneath the bowl. In this case the entire shank has been drilled out to 3/4" wide and around 2" long so its a fairly large chamber for such a small pipe. Also, even though its a very chunky pipe its pretty lightweight at just 1 ounce.I went on a Google search and couldn't find a satisfactory answer..