Antique Metronome

Picked this up for $6.99 at thrift store, it reminded me of the metronome my piano teacher had when I had piano lessons as a kid. I did some research on it a while back, but can't remember my findings. The company name is Maelzel, it has a paper scale with old style writing on it. I vaguely remember the company was in production late 1800's onwards, I feel like it'd be from the earlier part of the century, maybe 1920's. It is missing it's bottom part, I found an identical one for sale on a website for just under 100$, and a few similar ones on ebay for $30-$60. Any insight on this one is appreciated!