Contrary to superstition, thirteen CAN be a lucky number! Twice! This glass bong's double tree percs, each with thirteen arms, allow for the maximum filtration of your dry herbs and tobacco. Each tree perc is in its own chamber of clear scientific glass, so this pipe is made to last! Its 90 degree angle 14mm female joint, 4" sturdy base and bent neck also makes it easy to use and pass around to friends. In addition to function, this water pipe also has tasteful form with green glass accented percs and black glass accents on its flared mouthpiece and base.