Our newley double horned zong bong which features 19mm joint size. It is made of thick and high quality borosilicate glass. The 5mm thickness of glass water chamber area ensures that the base is stable and sturdy. The Zong! Is getting very popular due to its awesome design philosophy. The double horn means it has 2 spikes to make the Z pattern. The color combination make it very attractive. As always SmokeDay products are made using high quality materials.