Rackmount for Comcast Business Modem model CBR-T.
Many of my customers had their modems installed on a shelf so no brackets were included. I could not find them for sale anywhere, so here is my attempt to resolve.
There are 2 triangle supports that are not on the Comcast metal brackets that I added for rigidity (picture with 2 brackets has comcast metal version and mine). My 1st version didn't have these, and the back of the modem sagged. This support will be on the bottom on 1 side and top on the other when mounted, but they hold the modem straight without interfering with adjacent mounted equipment.
I included the blender file for anyone who wants to tweak the design.
The picture of my rack has 1 of this version (right) and original version without support (left); just adding one with the addition support made a huge difference.

Creality

Ender 3

No

Yes

100%