Gentex Corp. engages in the business of designing, developing, manufacturing, marketing, and supplying digital vision, connected car, dimmable glass, and fire protection technologies including automatic-dimming rearview and non-dimming mirrors and electronics for the automotive industry, dimmable aircraft windows for the aviation industry, and commercial smoke alarms and signaling devices for the fire protection industry. The company is headquartered in Zeeland, Michigan and currently employs 6,184 full-time employees. The firm's segments include Automotive Products and Other. The Automotive Products segment designs, develops, manufactures and markets interior and exterior automatic-dimming automotive rearview mirrors that utilize proprietary electrochromic technology to dim in proportion to the amount of headlight glare from trailing vehicle headlamps. Within this segment, it also designs, develops and manufactures various electronics that are value added features to the interior and exterior automotive rearview mirrors as well as electronics for interior visors, overhead consoles, and other locations in the vehicle. The Other segment includes Fire Protection, Dimmable Aircraft Windows, Nanofiber, Medical, and Biometrics. The company manufactures photoelectric smoke detectors and alarms, visual signaling alarms, audible and visual signaling appliances, and others.