This is 18.5" of thick glass and supreme filtration. The main filtration chamber has a donut barrel diffuser which creates minimum resistance airflow through the water pipe. It produces a steady and evenly distributed ingestion of smoke or vapor. A large water pipe like this is excellent for adding fun accessories. For example, an 14mm 90° matrix diffused ash catcher or an e-nail make great additions to this fine piece. We here at The Mushroom love this Water Pipe!