Review on 📏 HiLetgo 2pcs 0.56 inch Digital Voltmeter Ammeter - DC 100V 10A Amp Voltage Current Meter Tester, 3 Bits Blue + Red Dual LED Display Panel with Connect Wires by Khalil Hopp

The first block in my separate 24-28V supply burned out immediately I switched on the second 5V block and it seemed to work correctly, but the current accuracy was about 20% lower. The voltage accuracy is not acceptable out of the box, but at least you can calibrate the voltage with the regulator on the back. I increased the supply voltage, and at about 22V the meter went off and lit up. This may be ok with low independent supply voltage of 5-12V, but not useful for my 24V application UPDATE: It looks like a 7533-1 voltage regulator is used to get 5V for operation of the meter, but the maximum allowable voltage is most of the 7533 models are rated for 24V. So it can be good or bad as to whether it will actually work at or near that maximum voltage, and any spikes will see it across the edge. There is no way it will reliably go above 24V.