Another iteration of voltmeter case. Purchased on eBay, it is a very common and cheap device with 2 or 3 wires which are comming with just a PCB.

Use 2 x M2.5 hex screws on the back to securely close the case. Rectangle hole on the side is for wires.

6 x 2mm holes have been put on top and bottom for fixing it if required. Use M2.5 screws directly in the case.

Enjoy...