Review on 📊 bayite Pack of 5 Three-Wire Calibratable DC Mini Voltmeter: Monitor Car/Motorcycle Battery Voltage with 0-30V Range, Mountable Tester Gauge, 0.36" Blue LED Panel Display by Drexel Wortham

Pros: Looks nice. Its clear and easy to read 7-segment LED display. Very easy to use, only 3 wires. Cons: The input impedance is only 120 kOhm. As such, it will draw significant current from your load. With this thing, you don't have to track high-impedance signals. So you can't connect it directly to most sensors; must buffer the output of the sensor with an amplifier. You could at least buffer the inputs with an op-amp, adding only 3 cents to the cost. Another downside is that the entrance is not secure at all. I roasted one of them while testing. I switched the dial on the multimeter and suddenly the display went blank. So they are easy to damage, not enough circuit protection. All in all, for only $2.50 each, not bad.