If you have a mail slot in your front door, a lot of heat can be lost through drafts. This is not only annoying for yourself, but is also not good for the environment. Door-Line is a Dutch brand that has dedicated itself to making products in the areas of wind-proof and seals for housing. On letterbox- expert you can find a serie of Door-Line inside plates. An inner letter plate can be attached to the inside of your front door in order to prevent drafts through the mail slot. These letter plates are equipped with a brush and a draft flap for stopping drafts and pollen.