What interesting with this buck converter is it has a built-in 3-byte LED tube.

You could select what you want to read, whether it is the input or the output voltage. There's a built-in LED indicator that indicates the voltage. That is possible because this module has an integrated XL4015 IC. It also has 2 tactile switches to tell which the voltage you want to read.

You could change the correction value of your input voltage by short pressing the tactile button on the left or right to increase or decrease the value on the tube by 1 point. You could also store the correction value on the module, by long-pressing the button on the right side for around 2 seconds. The same commands are for adjusting the output voltage.

This module could accept voltages from 4V to 38V with the output 4V lessen than the input. The measurement accuracy of this module is +-0.05V. The output current is capped to 5A only.