6.5" Long Downstem for 18mm to 14mm
A Downstem is a piece of scientific glass that connects a tube-style water pipe to its slide bowl. It's easy to break and can get quite dirty so people like to have replacement options.
This particular down stem has an 18mm male fitting and 14mm female fitting. It's made to fit into a water pipe with an 18mm opening.
It leads up to a female fitting with a 14mm opening.