It's a 240V outlet. You would use it with a Dryer or Oven, for instance. That list is not comprehensive. May also be for an EV although it's not rated for outdoor if it's outdoors.

https://www.amazon.com/Guaranteed-Commercial-Industrial-Approved-Receptacle/dp/B099ZFQP5Q

u/kenbodian solved it with the comment above. Link to the original post

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