Construction Specialties, Inc. designs and manufactures specialty architectural products, particularly healthcare facilities. They make this unusual door, which has a second door within it:So what's the application?"Our barrier-resistant doors offer a unique solution for behavioral health facilities. [They] feature a small compact door within the main door providing staff easy access to a room if a barricade is used by a patient."Additionally, the door stiles are replaceable, should the patient damage them.