Lego Duplo flexi track, shorter (about 2/3 of original and ½ of original), optimized for printing with nozzle 0.4.
Tested, fits and works well.
Layer: 0.25mm
Infill: 30%
Filament: PETG
Notes: regarding colour: choose different filament colour than grey, for easy finding this flexi track in box with original tracks.. :-)