I recommend the Beamray. It has preset frequencies and uses sweep and pulse tones. I bought one when I contracted Giardia and went to a practitioner in Florida who ended the infection in just one session using the sound and light machine. They are expensive but easy to use. I have helped a number of my friends with the unit as well as animals. I have used it for systemic ringworm (whole body), pinworms, parasites from eating sushi, bacterial infections in cats etc.