VAISALA ANNOUNCES AGREEMENT TO ACQUIRE SIGMET CORPORATION IN THE USA Dec 23, 2005 Stock Exchange Releases Vaisala Oyj Stock Exchange Release December 23, 2005 at 09.00 Vaisala Oyj and shareholders of Sigmet Inc. have reached an agreement for the Vaisala acquisition, through its US subsidiary Vaisala Inc., of 100% of the SIGMET Corporation stock of Westford, Massachusetts. SIGMET is the world's leading independent weather radar signal processor and application software manufacturer. The purchase price is approximately 20 million USD. In November 2005, Vaisala announced its intention to enter the weather radar business. The acquisition of SIGMET supports this by complementing Vaisala's product and service offering. The SIGMET signal processing and application software products will continue to be available to all radar manufacturers and end-user customers. Vaisala's own weather radar, estimated to be launched in 2007, will be equipped with SIGMET technology. SIGMET was established in 1980 by Richard Passarelli Jr, Alan Siggia and Joseph Holmes, who all worked at the weather radar laboratory of the Massachusetts Institute of Technology, MIT, at the time. The company was founded in response to government and private sector demand for the types of systems they were developing at the MIT. SIGMET recently won a 9.6 million USD upgrade project for the US National Weather Service NEXRAD radar network as a subcontractor to systems integrator RS Information Systems of Virginia. Currently SIGMET employs 10 people in Westford, Massachusetts. The net sales in 2005 will be approximately 11 million USD. SIGMET Corporation will be merged into Vaisala Inc., and will continue operating as Vaisala SIGMET product line. Richard Passarelli Jr, Alan Siggia and Joseph Holmes will continue working for Vaisala. The Vaisala Group is a successful international technology company that develops and manufactures electronic measurement systems and equipment for meteorology, environmental sciences, traffic safety and industry. Vaisala employs over 1,000 professionals and achieved net sales of EUR 180.6 million in 2004. Vaisala serves customers throughout the world. In 2004, exports accounted for 97% of net sales. Vaisala's A-series shares are quoted on the Helsinki Stock Exchange.