Klein Tools MM100 Manual Ranging Multimeter

The MM100 reads AC and DC voltage up to 600V, and it defaults to the AC voltage range when you turn the dial to volts. That covers the 120V and 277V line-to-neutral and 208/240/480V line-to-line readings an electrician takes in a commercial panel, plus 24V control and DC battery circuits.

Current measurement on the MM100 is DC, up to 10A. That handles DC motor draw, control and battery circuits, and low-voltage system troubleshooting. For AC load current on a branch circuit or a motor, a clamp meter is the tool, since a meter with test leads means breaking the circuit to put the meter in series.

Yes, and it beeps. The MM100 has audible continuity with a loud buzzer, which matters when you are pulling on a cable in a mechanical room and cannot look at the display. It also has a diode test position for checking diodes and LED drivers, and a resistance range to 2M ohm for reading coils, thermistors and long conductor runs.

The MM100 is manual ranging, so you pick the range on the dial before you read. If you already know roughly what you are measuring, that is faster and it stops the meter hunting for a range on a noisy circuit. An auto ranging meter is the easier choice for someone who tests occasionally or works on unknown circuits, because it picks the range itself. Manual ranging suits an electrician who tests the same voltages every day.

That is what the data hold button is for. Press it and the MM100 freezes the reading on screen, so you can get the probes into a crowded gutter or an overhead junction box, then pull out and read the display. The buttons are soft touch, so they work with a gloved thumb.

The MM100 ships with a protective boot around the meter body, which is the part that takes the hit when it comes off a ladder or slides across a truck bed. It also has onboard lead storage, so the probes stay with the meter instead of loose in the bottom of a bag.

Two things cover it. There is a low battery indicator on the display, and a battery test function on the meter itself. A weak battery is the usual reason a meter drifts or reads low, so on a fleet of meters across a maintenance shop that indicator is what keeps a bad reading from turning into a bad diagnosis.

Order it as Klein Tools MM100. That single manufacturer part number is the whole product, there are no finish, range or kit variations to specify, so a purchasing agent standardizing a set of meters across crews can write one line item.