Made entirely of steel sheet metal. Basic version install by Polish Post office. Introduction slots placed from sides of mailbox secured by flaps. Empting the cases take place by insertion in frames of case the summary bag which causes the bottom open and the pours out to bag the content. During putting out frame from guide the bottom of case locked automatically. Boxes may contain mechanic system confirming receipt of post. Case have special lifting sling permitting on her installing in any place.