Includes knives marked as 440, 440A, and 440B. 440A is a high-carbon stainless steel with about .7% Carbon, used in most American production knives and in some handmade knives as well; works well through tooling. 0.60 to 0.75% Carbon, 1.0% Manganese, 16.0-18.0% Chromium and 0.75% Molybdenum. 440A is very popular with the handmade Randall Made knives. 440B has 0.75-0.95% Carbon, 1.0% Magnesium, 16-18% Chromium, and 0.75% Molybdenum.