This is based on Caleb Cox's Design for a multi-purpose flexible strap. I created a OpenSCAD design from it, so it is super easy to customize. You can change the length of the strap, number and dimensions of the holes or switch between elliptic and rectangular holes. Printing instructions: I used NinjaFlex and 20% Infill already seems enough, because the size actually does not require any. Be sure to print not too fast. With the ZXXY printer I needed to rise the extrusion multiplier to 1.05. Otherwise the outline layers were not connecting to each other. With elliptic holes the width in relation to the height should not be as much as with rectangular ones. In the final design two joints are enough to have a tight fit.