This is a variable size cable tie as seen in the pictures.  The white one is of course, the original for comparison.  There's one factor at the top of the *.scad file to scale the size of the cable tie.  You'll probably want to scale up the size of the cross section of the tie as you make it bigger.  I did 2 mm x 2 mm for the small and 3 mm x 3 mm for the one scaled up by a factor of 3.  I also increased the size of the balls on the ends as well.  All those settings are clearly marked near the top....and that's all you need to know, unless you want to play with it.

I created the shape of the cable tie using  Bezier polynomials to provide smoother transitions for the line to copy the shape of the original.  If you want to play with that, you can adjust the shape of the curve by adjusting the points in the control point array.  You'll see some red and blue points on the display during preview that go away when you render it.  Those are there to help assess what to change when you're adjusting the points for the Bezier curves.  I created one half of the cable tie as a line and then flipped it to produce the other half of the cable tie.

I consider this a first experiment in shaping a cross section and then extruding a shape up from the cross section lines.   If you're looking for openscad code to replicate something like that, it's in here.

I made my prints at 80% fill, first layer at 0.28mm with other layers at 0.2 mm.