Those will work as you dont need 4 digit. I have a few of them that I mounted in Radio Shack surface mount project boxes. I also mounted one in a regular wall switch plate cover like the type used in a house. Just cut the plastic and snap the switch into place then screw the cover plate to a home depot blue plastic electrical box. You can get the blue plastic box is a small capacity style.
Mine are 9 months old, seen various voltages, been turned on and off many times and they still work.
If you want to get crazy like some of us and see the 4 th digit for hundredths of a volt you can get a 4 digit adjustable. I dont like the 4 digit small non adjustable because they read high with say a voltage of 12.5 actually being 12.41 to 12.43
They are within spec but if we are going to watch hundredths, we dont need to be off by 80/100 or 90/100.