It is a timer for something .
Time clock. I believe that they still make them like that.
Just curious, what did this say? Any clues that this may be for exterior lighting, pool pump, grow light etc?
Sorry I read it wrong its instructions about the breakers they change new panel.
It looks like some type of timer. There is actually one of these wired to the water heater at my parents farm house so that it doesn’t reheat the water all the time. Like energy savings kind of thing
Something like this: