Founded in 1919, Alnor Instrument is a repair and service center for precision instrumentation. The company provides Alnor handheld instruments for contractors, facility personnel, building engineers, safety officers and industrial hygienists throughout the world. It also offers AirGard alarms and monitors that are used in retrofit lab hood monitor installations. Alnor Instrument, formerly known as Illinois Testing Laboratories, was acquired by TSI Incorporated in 1995. TSI Incorporated is one of the leading design and production companies of precision measurement instruments in the world. The company deals with aerosol science, air flow, indoor air quality, fluid dynamics and biohazard detection. It operates offices in the United States, Europe and Asia. TSI Incorporated maintains a location in Shoreview, Minn.