This 3D Model is a spiral with a sphere diameter of 16mm.
The hole for the necklace string has a 3mm diameter.
You can wear it as a pendant or combine it with another part "filler for sphere spiral".
link to filler for sphere spiral :
https://www.shapeways.com/product/QEQCGVMCG/filler-for-sphere-spiral-16mm
The purpose of it is to symbolise two parts, that complement to one another like it should be in a harmonic partnership.
This part "sphere spiral" can be made from a rigid material like silver for example.
The optional filler part has to be made from flexible material otherwise you will not be able to mount it.
To mount the filler part just screw it on the spiral.
The filler part snaps tightly into the spiral but with a needle-like tool you can lift it and screw it off the spiral again.