Abstract: A prefabricated unit including a wooden frame formed by a number of sections including a pair of jambs, a sill, and a header with a door or window operatively positioned in the frame and a plurality of metal frame extenders mounted on the exterior of each section of the wooden frame, the metal extenders being provided with a nailing fin that can be pivotally moved from a closed position for shipment and storage to an open radially outwardly extending position for attachment of the unit to an opening provided in a building.