Depending on its size and the related frequency, a singing bowl can have a stronger or weaker effect on different areas of the body. Small singing bowls are the Head Bowl, Heart Bowl and Throat Bowl; large singing bowls are the Pelvic Bowl, Solar Plexus Bowl and Universal Bowl. In addition, there are Sangha Meditation Singing Bowls, Zen Singing Bowls and Special Singing Bowls. The quality levels are called Peter Hess® Therapy, Premium and Classic.