Extech 380803 True RMS Power Analyzer/Appliance Tester and Datalogger Compact, battery operated datalogging appliance tester for analyzing AC/DC power loads Built-in Datalogger stores up to 1,012 readings (single record/continuous datalogging) Four simultaneous displays of Watts, Power Factor or VA, voltage or Hz, Amps True RMS voltage and current measurements of sine, square, triangular and distorted wave forms with a crest factor &lt; 5 Plug device to be tested directly into the power analyzer.Sampling (update) rate is 2.5 times/second