Production Glass
From Wiki Weed
Production glass is most commonly used when mass-producing pipes, and for this reason is both cheap and often unreliable. Prodo glass designs tend to be less extravagent, and is almost always less desirable than its counterpart, heady glass. The only time a production glass piece might be preferred over something of higher quality is in a risky situation where you don't want to risk your nice piece getting broken or confiscated by the law.