I picked this key up from a well known auction site as a restoration project. The tension spring bolt had broken and it was very dirty, however with a bit of time and elbow grease I managed to get it cleaned up. It looks great, though doesn’t get much air time.
The covers were made of formed Bakelite and had a tendency to get broken because of the two locating pins not being seated properly when the cover was installed and screwed down, or the cover not being removed vertically.