The variety of alloys utilized is sensational: weathering steel for aging, marine-grade light weight aluminum for weight cost savings

https://wiki-triod.win/index.php/Engineers_on_Copper:_Why_Custom-made_Chimney_Shrouds_Are_Defined_for_100-Year_Roof_Coverings

The variety of alloys made use of is magnificent: weathering steel for aging, marine-grade aluminum for weight cost savings, and duplex stainless for corrosion resistance in extreme environments.