Any idea what this is?

Noticed this beasty hooked up to my air conditioner of the house we bought recently:

https://preview.redd.it/cnybn2sqc7jh1.png?width=500&format=png&auto=webp&s=49ee1d55b182f0dfc2fc0b59963d6c484f539dc8

Is one of those things where the power company can turn off your AC when it gets hot?

Thanks