This is an electronic enlarger timer from back in the film days.
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Switches from one outlet to the other depending on the time set.
You set the time you want (to 1/10ths of a second up to 110 seconds) and push the button so it will switch the "safelight" off and the enlarger on, then at the end it switches enlarger off and "safelight" on.
This was a pretty deluxe timer for its use back in the day.
Might be handy for other hobby uses. The price is right.
Come pick this up for free!