This bowl stand is made for a 18 mm male joint. It isn’t everyday you run into a bowl stand like this. Look at how proudly it stands; knowing it will do its job well. The black color of this stand is beautiful – it works really well in contrast with the usual transparent parts and joints. The stand is made of high quality borosilicate glass that is very durable. If you are looking for a bowl stand for the 18 mm male joint that you have, then this is just what the doctor ordered.