"EDDY CURRENT FLAW DETECTOR IS COMPACT SELF CONTAINED LIGHTWEIGHT INSTRUMENT FOR LOCATING CRACKS AND FLAWS IN ELECTRICALLY CONDUCTIVE MATERIALS AND MAGNETIC AND NONMAGNETIC MATERIALS BY PERMEABILITY AND CONDUCTIVITY MEASUREMENT; IT HAS AN IMPEDANCE PLANE DISPLAY AND MOTORIZED BOLT HOLE SCANNER,EXTERNAL DISK DRIVE,IBM-PC BASED DATA ANALYSIS SOFTWARE; OPERATES ON ALTERNATING CURRENT - 115VAC,60 HERTZ - AND DIRECT CURRENT - RECHARGEABLE BATTERIES; IT HAS AN OPERATOR ADJUSTABLE FREQUENCY RANGE OF 50 HZ TO 3 MHZ AND AUTOMATIC SELF-CALIBRATION DURING SET-UP INCLUDING AUTOMATIC PROBE BALANCE"