The invention relates to an ultrasonic therapeutic device, which can be operated independently of an external power source. For longer periods of operation, for example by a trainer at a sports ground, the device can be operated using an external battery stack and for stationary operation, the electric...http://www.google.fr/patents/US20040171970?utm_source=gb-gplus-shareBrevet US20040171970 - Hand-held device for pain relief
