Small Shelf for Electronics

I made a shelf for my Verizon 5G Home internet router with a cutout in the back for cables to hang down behind it, could work for a wide array of electronics you want up on the wall. Max size screws I'd use would be 4mm diameter. There are 4 screw holes, but mine holds up perfect with just 2. Model in the pictures was made with PETG, only needs supports at the bottom for the cables cutout.