Wall Mount Filament Spool/Headphone Hanger

This is a wall mount filament spool/headphone hanger which was fixed on with screws.

Updated on 19 Aug 2018:
When I hanged up a 1kg spool, the cantilever arm sagged. Therefore, the hanger shall be redesigned to strength the rib for support. Please do not print this out for use or alter the design (i.e. increase the infill/wall thickness and increase the depth of web as shown in attached photo.) for your loads.
For the loading diagram as per attached, max.bending moment and shear force