Review on DROK Multimeter Voltmeter Transformer Two Wires by Joe Bailey

I have 3 of these to monitor a 3 phase alternator and have only tested them on the dyno so far. All 3 read the same. In order for the display to be bright, it must be at least 50 volts. I increased the current to 7 amps and everything reads the same. The 'Instructions' on the Amazon page is a bit odd regarding connectivity. Several reviewers mentioned that reading the amp never worked. If you're not familiar with current transformers, you might not have realized that the wire has to go through the donut hole. I don't know why anyone wouldn't just send it back.