Cable holder for End of 20x20 Extrusion

I couldn't find anything on thingiverse as a simple cable holder, cable tidy for the end of a 20x20 aluminium extrusion so I created this in Fusion 360.

Sliced in Simplify3D.

Printed on the Hictop CR-10

2 layers on the bottom, 2 perimeters, 3 top layers, infill 25%. Printed in black PrimaValue PLA that i have had for over 3 years and seems to still be printing really well.

11/10/18 - Added a round holder, I haven't printed this yet, but I used the same original file as with the squa