Holds the pieces of a disassembled four-part double-paddle together, so you can carry and store it easily as a compact package. 

The dimensions of the enclosed .stl files will fit a 30 mm paddle shaft with 27.4 mm diminution, 7 mm diameter lock pin and 30 mm distance between lock pin and diminution to shaft step, see caliper pictures. For you to validate whether the enclosed .stl files for the hodler and the clips fit your paddle dimensions I included a matching .stl file for a test tube. 

To implement your custom dimensions amend the parameters at the top of the enclosed OpenSCAD source file as detailed below. You may first render and print a test tube to validate your custom shaft and diminution diameters. The test tube has minkowski() roundings by default, so you will not have to deburr the inner circumference from possible "elephant foot" (overextrusion of the first layer). 

The computation of the minkowski() corner roundings may take excessive CPU time when rendering the holder (>30 minutes on my PC). So I disabeld it by default for the holder (parameter xyz_dmink = 0). Without minkowski() roundings you may have to deburr a possible "elephant foot". You may enable minkowski() rounding on the holder by setting xyz_dmink = wall-0.001. 

As always I am including the OpenSCAD source file for you to adapt and/or improve:

• Install OpenSCAD from https://www.openscad.org
• Launch OpenSCAD and open the enclosed OpenSCAD source file (/File/Open).
• Amend the parameters at the top of the file or even amend the code.
• Save your changes (/File/Save).
• Render the design (/Design/Render).
• Export the rendered design e.g. as a .stl file (/File/Export/Export as STL).
• Slice and print.

See my other designs at
https://www.thingiverse.com/thinger13/designs