Abstract: A seal for precluding an entrance of rodents or debris underneath a door. The inventive device includes a mounting assembly securable to a lower edge of a door, such as a security door or the like. A flexible seal is supported by the mounting means so as to extend downwardly from the lower edge of the door to contact a ground surface therebeneath. The flexible seal projects laterally of the mounting assembly so as to additionally contact adjacent lateral surfaces of the associated structure. The device allows an entrance door of the structure to be left open with only the security door closed to permit a passage of air currents through the security door while simultaneously precluding an entrance of rodents or debris underneath the security door.