The model is crossed bones that link together. My initial thought was for my dogs to wear on Halloween, but it could be used as general decoration as well. 

Whatever you decide to use it for keep safety in mind. They are not edible and I don't suggest letting your pet chew on it.

I only tested using PLA on a Prusa Core One on the following settings: .20mm height (Balanced mode on Prusa Slicer), .4mm nozzle, 15% infill, and all default settings. I did not use any supports, rafts, skirts, or brims.

The model is 30mm from center of ball to center of socket (roughly 1.25 inches). As an example, my dog weighs 50lbs (~23kgs) and 20 links was plenty to fit around his neck.