The Door-Line inside letter plates are not just useful for the mail. These plates also help to save energy through the weather draft. As a result, there is no longer any cold in the house via the letter plate. You place this inside letter plate at the back of your regular letter plate. The brush and the flap on the inner letter plate not only keep out the draft, but also prevent pollen from entering your home. With Frank you will find letterplates in different, subtle colors that fit into every household.