Keithley Instruments is a measurement and instrument company headquartered in Solon, Ohio, that develops, manufactures, markets, and sells data acquisition products, as well as complete systems for high-volume production and assembly testing. In September, 2010, the company agreed to sell itself to the Danaher Corporation, a Washington, D.C.-based conglomerate, for $21.60 per share. It was soon merged with Tektronix, Inc, which had been acquired by Danaher in 2007, and now exists wholly as a brand of Tektronix.