This is a case that was made for the eBoot LM2596 (Amazon Affiliate Link) converter. It is designed to have the incoming wires to go straight out (I was using a JST connector and there isn't enough room to do a hard 90) have have an outgoing USB cable out a single hole the other end.
Railing has been added! If you look at the input (side with 2 holes), the railing is on the corresponding side.
I have received a request externally to have 2 holes on both sides and a single hole on both sides. I will work on this request when I finish another project.
The F360 file can be downloaded for modification here.