This model is a true favorite and classic in our family. It is simply beautiful on the tree and so easy and fast to print. It should be printed in vase mode in shiny, glossy, sparkling filaments.
it can also be used as a napkin ring. Thank you Lucretia For the brilliant suggestion!
The sides works as springs and they are NOT fragile and also very easy to put on the tree.
There is also a heart shaped version of this:
https://www.printables.com/model/1117695-flexing-heart-ornament-vasemode

The author marked this model as their own original creation.