The raised boss in the centre of the gong is struck to produce a resonant sound. A different note is created by striking elsewhere on the gong. The harder a gong is played, the more its surface is activated, resulting in the whole surface loudly resonating with many layers of reverberation.
Some practitioners believe certain frequencies can focus on specific areas of the body, contributing to the healing of certain ailments.
If you want to target specific chakras, choose a gong based on its tonal frequencies.
Please note that the striker colour may vary.