Ever needed another tool to measure process signals when your calibrator is in use? There are two approaches to this : either have another dedicated tool in your bag like the Fluke 771 milliamp process clamp meter (which allows you to measure 4-20mA signals without breaking the loop!) or get a single multi-functional calibrating multimeter like the Fluke 787 or Fluke 789 which alongside their calibration capabilities are full-featured 1000V True RMS digital multimeters as well.