.Amprobe ACD-6 TRMS PRO Clamp-on Digital Multimeter 1000A includes TRMS measurement, auto/manual ranging, relative zero mode, auto shutoff, data hold, and much more. In most situations, the TRMS version of the meter is recommended in order to avoid large measuring errors; therefore, if uncertain always choose a TRMS sensing clamp to ensure measurement accuracy for all of your applications.