The pipe can become hot during smoking, so the plastic mouthpiece goes on the end of the glass pipe.
The mouthpiece insulates the mouth from the hot pipe and prevents burns and cuts from the pipe.
Every person should use their own mouthpiece to prevent disease transmission such as Hep C.
The coloured mouthpieces help to limit the accidental sharing of equipment and reduce the transmission of BBVs.
If a new mouthpiece isn’t available, then an alcohol swab can be used to clean the equipment.