Summary

Another thing noone but me will probably find useful, but if anyone can use it, here it is.

I bought a link balancer with 4 jacks and wanted a cover for 2 jacks. I made the other covers because it was easy to modify the first design. They install easy enough, and stay put, but the tabs tend to break when removing them, unless you are careful. The original covers are metal. The quad cover is snug, but works fine.

This is a long story, I will try to make it as short as I can.
I have had a few Barracuda link balancers, web filters and firewalls to play with. They are cheap ($25-$30 including shipping) and work well for a low powered server. They have PCIe NICs without RJ45 jacks, that are cabled to a card on the front. The front card has a bunch of relays that when powered off, create a pass through on the jacks (which can create a broadcast storm if you have them in a nonstandard configuration). I made a simple front card in Kicad to run the cables straight to the jacks, for a web filter with two jacks a few years ago that I use as a file server (I hosed the onboard nic by playing with the bios; so I use the PCIe nics bonded). I recently got a link balancer, and put one of my cards in it, but didn't want the gaps from the quad jack cover. So I made the dual cover. I don't need the other covers, but they were easy to make from the first, so I made them in case I wanted them in the future, or if they could help someone else.

They would be fine in PLA (the metal cover in my closet is ~ 95F or 35C); but I printed them in black PETG at 0.28mm layers. I print them flat, so supports and infill don't matter. I know printing them vertically would make the tabs stronger, but since the tabs only seem to break when removing the cover, I think it is better to save print time, supports and post print cleaning.