LED Voltmeter mount

I got some of these cheap voltmeters: https://www.gearbest.com/development-boards/pp_134717.html?wid=37 and I made an enclosure for them. I saw that other meters on the website (https://www.gearbest.com/lcd-led-display-module/pp_595446.html) that had 'mounting ears' located in the center so I put in holes for those too - I have not tried those.
The screws I used are the same for mounting CD-ROMS in PC cases. These were handy for me, size: Screw M3 x 0.25
There is a small cutout that can be enl