 9. If you prefer the "Sonovac" ultrasonic cleaning mode, press the    indicated blue button. When the twin panels open, pull forward by    rings A & B. For cleaning the hands, use in this position. Set the    timer to positions 10, 20, 30 or 40...indicative of the number of    seconds required. The knob to the left, just below the blue light,    has three settings, low, medium or high. For normal use, the    medium setting is suggested.  