Greetings, and a question or two. I have a recently acquired Rubberset 153, a model I've seen referenced here once or twice, and I posted photos several days ago in the acquisition thread. This is a bakelite handle, with black ferrule. In the reference material I've found, it looks like some of the bakelite Rubbersets have ferrules that are threaded, or that screw off. I don't believe the one I have is threaded, but am not sure. Is there some way to tell, by model number or appearance? Also, are there any other special features on these brushes to be aware of when re-knotting? Thanks!