I have a sony surround sound system and the rear speakers always sat on the arms of the sofa. I made these to mount them on the wall behind me for a much better sound.

There is rescess for screws and a gap to put the cable through.

While maybe I should have made a L&R version with the cable hole on the otherside you can use the 1 model for both the left and right rear speaker.

I printed in BL PLA CF and it came out amazing.