The invention relates to the field of hygienic care of the human skin and for performing certain dermatological procedures as removing blackheads and opening pimples with an ultrasonic applicator. The applicator or tool, which is used in conjunction with a selected fluid, has a contoured configuration...http://www.google.se/patents/US4040414?utm_source=gb-gplus-sharePatent US4040414 - Ultrasonic personal care instrument and method
