Ideal 61-763 TightSight 660A TRMS AC Clamp Meter is a True-RMS meter that includes TightSight display on the bottom to provide convenient measurements in difficult to reach environments. Ideal 61-763 TightSight 660A TRMS AC Clamp Meter is a digital clamp meter providing measurements of AC current, AC/DC voltage, resistance, capacitance, continuity and frequency.