http://shop.grasscity.com/cgi-bin/grasscity/Z2.html I am thinking about buying that bong but I have some questions it. Is that a glass on glass bong? The bong I order has to have a 14mm joint stem. The reason for the 14mm joint stem is because I will be hooking it up to my vapor brothers unit using a custom coupler and the coupler calls for a 14mm joint. How many mm thick is the glass on the bong? Thanks in advance for your help.