Quartz tuning fork has a fixed resonant frequency by striking. At present the most frequently frequency tuning fork used for musicians is 440Hz.

It mainly used for tuning instruments, also used to test the patient's hearing. And it is used as healing tools in some special treatments, such as sonopuncture.

Sonopuncture: a kind of acupuncture and moxibustion, but don't use a needle but use ultrasound whatever to stimulate the disease treatment. It also called sound wave therapy, sound healing or ultrasound therapy.