Note - after making this part I learned that these antennas have magnets in them: https://www.reddit.com/r/pcmasterrace/comments/wtxpqq . I still like the way this part looks better than using the magnets but you might prefer a different option! Thanks @Bull3t for setting me straight.
PC case mount for the 2T2R "Sharkfin" Wi-Fi antenna that comes with ASUS motherboards. Includes a hidden area to stow extra cable to the antenna.
The case this is sized for is the Thermaltake Core G21 Mid-Tower case, which has a protruding thumbscrew near the top-back corner. This gives a solid surface with which to “sandwich” the antenna against the case, and a lip around the edges of the mount keep everything snug. The thumbscrew might be in the right place for other cases, but I wouldn't count on it.
The other option excludes the thumbscrew cutout so you could potentially mount it to the case with double-sided tape, velcro, etc. I personally haven't tried this but figured I'd give some options!
The author hasn't provided the model origin yet.