Extech EX530 True RMS Digital Industrial Multimeter is precise with its 40,000-count resolution LCD screen. This tester is waterproof (IP67), has a sturdy design, and is part of the Extech 500 Series. It takes TRMS AC measurements for accurate AC Voltage & Current readings, regardless of waveforms. CE, EN61010 CAT IV-600V, and CAT III-1000V safety-rated; Extech is the only company who offers this on this type of meter. The RMS version of the meter is recommended to prevent errors. RMS versions ensure accuracy regardless of interference.