Review on PEMENOL DC-DC CNC USB Step Up/Down Power Supply Regulator Module: Adjustable Boost Buck Voltage Converter with Digital Display Voltmeter Ammeter and Battery Capacity Tester by Tyshawn Adams

I bought this to have an easy and portable way to check voltage on the go. I like that it works both as an ammeter and as a power supply. It's very easy to use. It has multiple functions: 1) it's a pull-down/boost power supply, 2) it's a voltmeter, 3) it's an ammeter, 4) it's a USB-powered thermometer. It is well made and compact. The buttons aren't impressive, but they are functional and work well enough. It feels comfortable and is reliable. It was a bit difficult to use at first, but once you remember a few things, it's easy to use. Pressing and holding the power button for 10 seconds toggles between two modes: power supply (they call it PER) or multimeter (they call it VAH). Only voltage can be set as a current source, but it can be rotated. switch it on or off and you will see the current load. In this mode it offers over current protection and I tested this by shorting the outputs. It showed a bug that was impressive for such a product. As a multimeter, it's easy to set up and accurate enough for simple projects. I particularly liked that it is very easy to use to measure the current utilization of projects. Note that when used as a multimeter, it must be powered from a source (via USB-A ports, USB-C jack or Micro-USB jack).