That is a no-longer-made (since 2012) Paragon time clock. If the dial keeps time (moves automatically) you can get trippers for it (Intermatic trippers won't work):
PARAGON X2772 657699 Series Time Clock Trippers
If not, you need to replace it with an Intermatic T101R timer as it appears to be a 120V time clock. There is also an after-market mechanism that will fit that enclosure:
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