When installing some Tein EnduraPro Plus dampers on my Model Y Performance, I found that the OEM rear shock dust boot retainers didn't fit onto the Tein damper. This ring is to be printed in TPU (90-95A shore hardness works well) so it can stretch over the larger cap on the top of the shock and then the OEM dust boot clips onto it.
The author marked this model as their own original creation.