Crack cocaine is inhaled from a small glass pipe. This is often called a stem. It has a funnel-shaped 'bowlpiece' where the drug is put to be smoked. There is a 2 to 3 inch long stem attached that the smoke travels through on the way to the consumer. These stems may be used in waterpipes, such as 'bongs' or 'bubblers', in which case about a 1/2 inch of the stem is submerged in the water and the smoke is sucked out through the water to the consumer. These stems are also used to inhale methamphetamine. When used for crack cocaine or methamphetamine, the stem is generally used as a standalone unit, without any water or attachment of any sort. After prolonged use, the glass from the stem may deteriorate from exposure to heat as well as acidity, and may become brittle and break or crack easily.