An internal reflector is more efficient than standard external reflectors. CAD technology allowed the development of reflector headlamps with nonparabolic, complex-shape reflectors. This was an array of four diameter reflectors surrounding a single square reflector. Parabolic trough and concentrating linear Fresnel reflectors are classified as linear focus collector types. Others use incandescent bulbs mounted in reflectors. Some designs add neutron reflectors or absorbers. Valiants got new rectangular side marker lamps with federally required integral reflectors. Decorative bezels and optical reflectors are commonly made of polycarbonate. The first four Sirius spacecraft used more traditional parabolic reflectors. Both trims featured required US amber side reflectors and lights. Round lamps with built-in multifaceted reflectors are widely used in residential and commercial lighting. This illumination could then be directed by reflectors and lenses. Other (normal) bikes need reflectors and lights. It makes use of the special properties of parabolic and hyperbolic reflectors. Curtains, reflectors, and intensity reducing shields are used to give soft light.