Hardware Hanger
Every electronic device seems to have that little keyhole in the back that defies the ability to get an exact line up with a couple of screws ( which have to be just the right size head and that is naturally smaller than everything you have). This is my solution. slip one of these in each keyhole on the device, place a drop of superglue on the back of each and press the device up to the wall. For lightweight devices, that is all that need be done. For heavier, a small flat head screw can be used but make sure it doesn't stick up above the top of the hole. Do NOT hang heavy items with these. The ABS plastic is only 3.5 mm wide at the stem.