SW Fillis Stirrups are made of the world's finest 18-8 (chromium/nickel) stainless steel. This alloy is best for stirrups because it extremely strong, resists salt and acids found in all stables, and will never rust or spot. Our stirrups are investment (lost wax) cast from carefully crafted models to insure consistently perfect quality. Even with these advanced production methods, every stirrup is hand inspected. These are beautiful, nicely weighted Fillis irons at a reasonable price.