This time it's another Vintage "look a like" An early Camelback lever key, unfortunately original keys of this style were very hard to use with a heavy none adjustable leaf spring fitted under the pivot, I thought I might try a small coil spring hidden away in the nose of the key (below) that can be adjusted from under the base to make a respectable action,  it works quite well considering it is basically quite simple, it has a nice Railway telegraph clatter to it, yet could easily be used for demonstrations vintage telegraphy or just as a key for special occasions :()