Piece for joining two sections of matchbox car track together. A friend from work had me design and make a couple of these for his kids' race track set. He claims they are working better than the original connectors and is using them in the tough spots that used to come apart easily when the cars went over them.I used .08 layer height and about 45 mm/s. It took just under 2 hours to print two with my settings. I'm sure .1 layer height would do fine.