FUNCTIONS AS MOTORIZED HELICAL SCAN PROBE DRIVE UNIT FOR INSPECTION OF BOLT HOLES OR TUBING ENDS; VAR SPEED CONTROL FROM 8 TO 60 RPM; 40 REV PER IN.PITCH; POWER 115/230 VAC; LIMIT & CLUTCH SWITCHES; 0.188 TO 1.500 IN.ABSOLUTE OR DIFFERENTIAL PROBES; HANDHELD ORW/TEST FIXTURE