The series of alloys utilized is sensational: weathering steel for aging, marine-grade light weight aluminum for weight savings
https://www.scribd.com/document/1058827467/Snow-Guards-Not-A-Surprise-The-Century-Scale-Case-for-Customized-Copper-196153
The variety of alloys utilized is spectacular: weathering steel for aging, marine-grade aluminum for weight financial savings, and duplex stainless for corrosion resistance in harsh environments.