A case invented when i burned pretty expensive dc converter by touching metal parts.
This case is completed with buttons and knobs.
You can cut pcb and solder a switch as shown. I like switches. They must be everywhere.
But without switch it will go.
Compare naked and cased part on photo.
You'll need 2 or 4 m3 screws and this board (if you have not).
This board converts 4V-40V to 1V-37V dc voltage which is pretty good for all home appliances and arduino and other projects. It has voltage display for input and output (switchable with button). It also can be used as voltmeter if you dont need to convert.