Accurate frequency measurements on adjustable speed drives (ASD) due to Fluke-designed low-pass filter Captures intermittents as fast as 250 µS with Peak Capture Switchable high display resolution allows 6000 to 20,000 counts – lets you see small changes in displayed readings.CAT III 1000V, CAT IV 600V safety rated Measure up to 1000 VAC and DC; Operating Altitude: 2000 m