Gentex, founded in 1974, is a manufacture and marketer of electro-optic products, including automatic-dimming rearview mirrors for the automotive industry, and fire protection products for the commercial building industry. Its interior and exterior automatic-dimming automotive rearview mirrors utilize proprietary electrochromic technology to dim in proportion to the amount of headlight glare from trailing vehicle headlamps. The company manufactures more than 60 models of smoke alarms and smoke detectors, combined with over 160 models of signaling appliances. It has also developed a light-emitting diode technology that yields synthetic white light suitable for illumination and signaling purposes. Gentex is headquartered in Zeeland, Mich., and has offices in Livonia, Mich., Germany, France, the United Kingdom, Korea, Sweden, China and Japan.