WASHINGTON, D.C. and SOLON, Ohio - Danaher Corporation and Keithley Instruments, Inc., announced today that they have entered into a definitive merger agreement pursuant to which Danaher will acquire all of the outstanding common shares and Class B cmmon shares of Keithley at a purchase price of $21.60 per share in cash for an enterprise value of approximately $300 million net of cash to be assumed. The acquisition has been unanimously approved by the Keithley board of directors.Keithley Instruments, Inc. designs, develops, manufactures and markets complex electronic instruments and systems geared to the specialized needs of engineers at electronics manufacturers and academic institutions for research, product development, high-performance production testing and process monitoring. The company currently offers approximately 150 products used to source, measure, connect, control or communicate direct and alternating current signals. Keithley's product offerings include integrated systems solutions, along with instruments and data acquisition modules that can be used as system components or stand-alone solutions. Upon closing Keithley will be part of Danaher's Tektronix business.The acquisition is subject to customary closing conditions, including the receipt of regulatory approvals and adoption of the merger agreement by Keithley’s shareholders, and is expected to be completed during the fourth quarter of calendar 2010. A partnership affiliated with Joseph P. Keithley has agreed to vote a number of Class B common shares representing 19.99% of the voting power of the Company in favor of the merger.