The variety of alloys used is stunning: weathering steel for aging, marine-grade light weight aluminum for weight savings

https://www.scribd.com/document/1042029003/The-Heritage-of-Hand-Fabricated-Metal-Customized-Leader-Boxes-Designed-to-Endure-a-Century-198695

The range of alloys used is stunning: weathering steel for aging, marine-grade aluminum for weight savings, and duplex stainless for deterioration resistance in harsh climates.