When it comes to durability, thicker is always better. It doesn't take a genius to tell you that. Although, I'm sure that a genius would also tell you that.
Many people think that borosilicate glass bongs inherently are fragile and easily broken. Some are, but believe it or not, there are many pieces so thick that they can take quite a beating. The typical glass bong is made with 3mm-5mm thick glass. A thick glass bong is anything made with 7mm or 9mm thick glass. The extra thickness help prevent breaks when you bump into and knock over your glass water pipes. Some 9mm bongs can even withstand knocks off of table tops.
Glass pieces come in all sorts of thicknesses, styles, and shapes, and this collection can help you begin the process of finding the right one to suit your preferences-- and your clumsiness. Keep in mind the extra thickness does also make these piece almost twice as heavy as the typical bong, which some people don't like, but most people love.