Bong bowls are a removable slide that attaches to a bong and hold the dry herb. For many smokers, bongs offer the most enjoyable smoking experience possible. Smoking out of a bong has many advantages: the water filters the smoke, and the cooler hits are more enjoyable. But in order for a bong to work correctly, you need a compatible bowl. Compatibility depends on size and shape. Bowl pieces generally comes in two sizes 14mm and 18mm. A good buy whether you need a replacement slide or just want some color bowl pieces to add some life to your bong.