Company Profile TSI Company Profile An international leader in measurement technology for over 50 years, TSI Incorporated ( designs and manufactures precision instruments used for respirator fit testing, exposure monitoring, contamination control, indoor air quality, ventilation testing, aerosol research instruments, and other key parameters in the environment. Especially within the segment Gas Flow Measurement Devices TSI offers a wide product range, which includes Mass Flowmeters, High Performance OEM Flow Sensors and Certifier FA Test Systems, to suit various applications such as patient ventilators and other medical devices. TSI serves the needs of industry, governments, research institutions and academia.