The Tudor Collection Internal Letterflap Smooth Black Iron works well on rustic, wooden front doors. It measures at 256mm x 84mm and is sold individually, complete with fixings. Smooth Black Iron Letterflap The smooth black iron finish does not have deep surface indentations like many other black finishes - this gives it a more modern feel. It is made from malleable cast iron, treated with a zinc phosphating process and then powder coated to provide a durable finish.