Forged steelWhat kind of materiel is it made of?
underground water valves going into the houses here, use that. Also fire hydrants use a larger 5 sided socket, or wrench.As an example, Snap-On carries a 5 sided 3/4 inch socket. But you have to be in the business to acquire one. The truck drivers aren't even aware of them. I can't specifically identify the use of such a wrench but it's not that unusual.
.