The downstem is the glass tube that connects your bowl slide into a bong, filtering smoke through water as it passes through. These glass stems are generally measured from the bottom of the frosted joint to the tip. Typical downstems connect the 18mm joint in your water pipe and convert that into a 14mm joint to fit most bowls, but we have both 14mm and 18mm downstems. Some downstems have percs that allow for extra diffusion, however triple slitted downstems are the most common. We offer every size of downstem available, making us your number one stop when it comes to buying downstems online!