This hub is pressed for attaching to the dimmer. The disk is held in place by three small plastic teeth, which are in turn reinforced by a metal ring. The problem is that these plastic teeth break off very easily when you do not exactly in the center pushes the dimmer for switching - in other words, constantly.
In my opinion this is a bad design. Due to the already built-Busch-Jaeger range I have no other choice than new Twistdimmer nachzukaufen central disks regularly.
