The variety of alloys utilized is stunning: weathering steel for patina, marine-grade aluminum for weight savings
https://www.scribd.com/document/1058495293/Hold-the-Drift-Copper-Snow-Guards-that-Protect-for-Generations-134579
The series of alloys made use of is stunning: weathering steel for aging, marine-grade light weight aluminum for weight savings, and duplex stainless for rust resistance in rough environments.