I'm sure this s a replacement part because it looks nothng like the pics I've seen of other Lyman 61 thermostats.
Sorry for the out-of fouc shot of the text on the side, it reads:
American Thermostat Corp. South Cairo NY
Model B-200 1600W 115-236V AC only
Seems like a pretty beefy unit for this little melter. I don't think that many come with 1600W thermostats.