A wall compatible with Echo Dot 4th and 5th generation that fits with most screws that are 4mm and below in diameter with 8mm and below screw heads. The measurements are: 

Printed With Supports (You may want to increase the support z distance as I spent around an hour removing them), 0.2 mm layer height, and gyroid infill as it is one of the strongest. 

I used wall anchors, but these are optional if you screw into a stud. I also uploaded the Fusion 360 file so that you can modify it if you need to.