Review on 💡 Musou USB Safety Tester: High Precision Multimeter for Charger, Cable, and Power Bank Testing - Amp Voltage Power Meter with Test Speed, DC 5.1A 30V Capacity - Black by Jay Maryland

I've been using this very consistently for a while and it's useful. It has a lot more power than abuse, but its main purpose for me was to detect and prevent dirty electrical spikes. First I wanted to test 5.01v. - 5.14V devices, but I find that they are most commonly used as a 110V direct wall outlet with 500J surge protection. USB outlets do not have 500J surge protection, so this device serves as a vigilant electrical company for quality control. The voltage is typically 5.06V, but the 110V AC goes through the AC/DC converters in at least 1 stage. Depending on what device is being USB charged, a splash of dirty electricity can mess up the 5VDC, but hopefully the amperage will not be affected. I have not tested this meter for more than 5.15V at about 0.61A. Not fast charging at all, but this gauge is unaffected. Eventually I might hook this up to a DMM and measure the resistance in ohms. It feels slightly warm during use, which is a good sign of low resistance and power dissipation. This meter can measure milliamps and mAh, but these measurements have proven to be completely unreliable in the industry. I believe this meter is correct as I set it up and many high mAh devices will not have as many mAh as they advertise.