Mini LCD Voltmeter with adjustable pot.

Power Range: 2.5v to 30v

Measurement Range: 0v to 100v

Display Dimensions:  10mm x 22mm 

The difference between the 2-wire and 3-wire 0.28' voltmeters is that the 2-wire version is powered by the same wire used for measurement (red), because the voltmeter's onboard electronics have a minimum voltage requirement (~2.5v) and a maximum voltage tolerance (~30v), this is the maximum range that can be measured using the 2-wire voltmeters.

With this 3-wire version, the voltmeter's onboard electronics are powered by the 3rd wire (yellow), the same ~2.5v to ~30v range is still needed to power the voltmeter but the measurement range is independent, from ~0v to ~100v.   For example, you connect the yellow wire to your BAT+ to power the voltmeter and connect the red to 510+ to measure the output voltage.