I needed a quick way to have laptop and phone chargers quickly accessible under the table, yet wanted that the cables can be quickly wrapped up so that vacuum cleaner or the like wouldnt start to fight dangling cables and cables on the floor.
Its simply mounted with two wood screws (3mm, e.g. 20mm length)
No supports needed. I printed in 0.2mm layer height.
Fusion 360 Design is here: http://a360.co/2xXhfYR