Review on 🔌 DEVMO XL4015 5A DC Buck Step-Down Voltage Power Module with LED Voltmeter - 2PCS for Adjustable Conversion by Jeffrey Nunes

I noticed that the left button toggles the display and LEDs on and off and acts as a 'decrease' button for setup mode. The right button toggles between displaying the input voltage and the probable output voltage. A long press on the right button will flash the screen, and from here you can set either the output or input voltage(?). This value is "saved” by pressing and holding the right button again. However, as far as I can tell, nothing other than the input voltage will affect the output voltage - I haven't been able to get a buck/boost converter to output anything other than its input voltage through any combination of inputs. So I think the product is defective or a scam as neither of my two products worked and it's unlikely to be a coincidence. EDIT: They work fine, turn the potentiometer counterclockwise at least 20 times if it doesn't. change output. I received this guide in a box with another similar product and decided to try it on them and don't you know it worked?