Glass bowls are an integral part of both bongs and dab rigs, serving as the component where you place your dry herbs or concentrates before vaporizing or smoking. Glass bowl pieces come in different sizes, shapes, and designs. Bowl size affects the amount of herbs that can be loaded at once, while shape determines airflow and smoke density. Some designs feature color-changing properties with use, while others may have decorative elements like marbles or fumed glass. Ultimately, the type of glass bowl piece chosen is based on personal preference and the desired smoking experience.