The benign type is seen in benign lesions such as benign tumors and following trauma. An aggressive type is seen in malignant tumors, but also in benign lesions with aggressive behavior, such as infections and eosinophilic granuloma.
When setting up a Hookah air system, you will frequently need an array of metal fittings. For use around water, you should use stainless steel or brass fittings only. This is especially important when diving in salt water. Fittings made of ferrous metal will rust or corrode when used in, or near a water environment.
Opening a hookah bar -- or any venue -- that serves alcohol can create barriers in terms of licensing, age limits, and safety from accidents. A very popular drink to serve at hookah bars is actually tea. Veteran hookah smokers will tell you that tea helps keep their throats smooth and greatly enhances the flavor of the tobacco.