A bowl (also called a slide) is an essential part of every water pipe. At our Online Head Shop we offer a selection of American made glass replacement and upgrade bowls and slides from brands such as Grav Labs, Franticus, Empire Glassworks and more.. A glass bowl or slide attaches to a water pipe and serves one very important purpose: it holds your dry herb. Knowing whether a bowl will fit a certain water pipe depends on the joint size and gender of that water pipe. Have questions? Feel free to contact us, we would be happy to help you find the right bowl for you.