Ultrasonic/Contact Stethoscope - The 2047U/C combines the features of a standard electronic stethoscope - with those of an ultrasonic (sounds higher in frequency than the ear can hear) detector. - http://www.tscm.com/mlk2047.html
Ultrasonic Blaster - sonic shockwaves - http://www.amazing1.com/ultra.htm
Cavitation energy meter (ppb, Inc.) - Meters energy and frequency in ultrasonic and megasonic cleaning tanks used in the semiconductor, wafer, disk drive, flat-panel display, electronics and parts precision cleaning industries. - http://www.megasonics.com/