TSI is no stranger to a good test. Founded in 1961 as Thermo-Systems Inc., TSI makes sensors and instruments used in a wide range of environmental safety and quality control applications. The company's products monitor air quality, temperature, and humidity in working environments; measure pollution conditions; detect gases and analyze gas pressure and temperature; and measure the flow rate of liquids. Wholly-owned subsidiaries include Environmental Systems (products for outdoor environmental monitoring), DICKEY-john (instrumentation for agriculture and public works), and Tekran Instruments (mercury monitoring).The global company has offices in China, France, Germany, India, Singapore, the UK, and the US.