The Cardinal PT1875Z is a 4' Poured Tread ZAM® Steel. ZAM® is a hot-dip coated steel sheet that has a layer of Zinc, 6% Aluminum, and 2% Magnesium. The effects of magnesium and aluminum together allow our ZAM® coated steel panels to have excellent corrosion resistance, scratch resistance, and formability. This is a genuine Cardinal product.