This is a machined aluminum replacement part.  One link is included with your purchase.  Owners of Dremel 1671, JET and Craftman scroll saws have also bought this.  The distance between the bores is 1.375 inch and the bore is a slip fit for a 16mm OD bearing. An epoxy or thread locking compound is required to retain the bearing in the link. 

Originally I tried a 3d printed plastic replacement, but it broke too easily.  That is why it is machined out of aluminum.