EOTech designs, manufactures, and markets electro-optic products and systems. The company is headquartered in Ann Arbor, Michigan. They produce holographic weapon sights for small arms that have been adopted by various military and law enforcement agencies as close quarters battle firearm sights[citation needed]. They also have roots in the Environmental Research Institute of Michigan (ERIM), a non-profit R&D institute[citation needed]. Of the many inventions by ERIM researchers, some were in the fields of synthetic aperture radar, laser holography, and aircraft head-up displays.