Amprobe ACDC-600A & ACDC-600AT Digital Clamp-On are quick AC and DC current-only measuring instruments. The ACDC-600A is an average sensing instrument calibrated to read out in RMS, while the ACDC-600AT is a TRUE RMS measuring instrument for accurate measurement of loads with distorted waveforms or systems suspected of having harmonics. Both models feature a 31⁄2 digit LCD readout with annunciators for AUTO (-) POLARITY, DECIMAL POINT, (LOW BATTERY) “-”, DC, AC, and HOLD. They also have a wrist strap to prevent slipping and a data hold switch to freeze the display reading.