Beaker water pipes are modeled after the classic laboratory beaker shape. In order for a water pipe to be classified as a "beaker", it has to have a wide flared base that tapers up into a straight neck tube. The predecessor to the beaker design is the Erlenmeyer Flask, a beaker that was designed to maximize the volume and surface area in the bottom of the chamber. This allows more water to be used to cool your draws.
Maintaining your beaker can go a long way to keeping your draws flavorful and smooth, check out our guide on how to clean your water pipe here.