These are shelf brackets that are optimised to be printed on a small printer like the prusa mini, a1 mini etc.. there is strengthening geometry you may need to split the file and use them as modifiers depending on your slicer, if you are able to use them you should be able to get away with 2 walls and thin infill, otherwise strengthen as you feel needed. no support required, go nuts with generic settings they are super easy to print. 

offset mounting to avoid the super long screw driver extension dilema with a lot of shelf brackets.