This is a remix of thing:745463 designed specifically for the DROK LM2596 Voltage Switching Regulator available online at places like Amazon. The case includes a space for the LED voltage readout and holes designed to align with the LED display select buttons for Input / Output voltage and the voltage up / down. There are also two plastic pins which can be used to make selections.
Just a note that the voltage regulator just sits in the case. I used some double sided padded tape to keep it in place, but it isn't really necessary. You could pass short M3 bolts (or small screws) through the board and out the back slits if you need to mount it permanently.