The device has a treatment head with eight permanent magnets distributed uniformly about a circle at 45 degree intervals with alternating North-South polarity and an ultrasonic transducer in the centre of the treatment head. Four magnets (2.0-2.3) are alternately connected to the input of an amplifier. A further four magnets (3.0-3.3) are connected to the output of the amplifier in alternation with the fist four magnets. The amplifier can be switched between inverting and non-inverting operation.
