A light fixture or luminaire is an electrical evice used to create artificial light or illumination. A complete lighting fixture unit consists of the light source or lamp, the reflector for directing the light, an aperture (with or without a lens), the outer shell or housing for lamp alignment and protection, an electrical ballast, if required, and connection to a power source. A wide variety of special light fixtures are created for use in the automotive industry, aerospace, marine and medicine.