The healing power of sound: set of 7 crystal singing bowls for holistic balance & wellbeing The following is an overview of the sizes, keys and qualities of the crystal singing bowls in this set. It is assumed that each key is connected to one of the seven main chakras. The sound of the corresponding crystal singing bowl should have an effect on the respective chakra. 432Hz crystal singing bowl approx. 15.2 cm (crown chakra, tone B) 432Hz crystal singing bowl approx. 17.8cm (forehead chakra, tone A) 432Hz crystal singing bowl approx. 20.5 cm (throat chakra, tone G) 432Hz crystal singing bowl approx. 22.9 cm (heart chakra, tone F) 432Hz crystal singing bowl approx.