This 1943-S war nickel is an off-metal, and is struck on a Lincoln steel cent planchet. The coin weighs 2.7 grams, is steel instead of the silver alloy mix of nickels, and also is smaller than a normal nickel with parts of the lettering cut off around the rim. Silver war nickels are scarce struck on steel cent planchets, and even examples such as this with corrosion are worthwhile coins.
NGC AU details corrosion. Typical corrosion is seen on both sides of the coin, but it has been nicely cleaned up (compared to some examples) and shows lots of the steel planchet in addition to the specks of gray and pitting.