Wood frames are an assembly of structural members that are secured to a rough opening to accommodate doors and windows. Wood frames contain all of an opening's elements, including ornamental infill such as glazed sashes. For both interior and exterior doors, the frame is recessed to accept hinges and a strike plate, where fasteners or deadbolts extend into the frame for security. Wood material is not a good conductor of heat, a fact which allows for energy efficiency in exterior doors and windows. Structural members may include a head jamb, sill, mull and side jambs, depending on the type of opening. Factory-built frames are available with prefinished, unfinished, or primed surfaces; factory-built window frames may also integrate aluminum or vinyl cladding.