Testo, Inc. is a world leader in the design, development, and manufacture of portable test and measurement instrumentation. Backed by 60 years of measuring engineering experience, our mission is to provide the best quality, service, and value in the industry. In addition, Testo is recognized as the leading worldwide manufacturer of portable combustion efficiency analyzers and air emission analyzers. Testo has become a major supplier of HVAC, critical HVAC, refrigeration, airflow, and environmental monitoring instruments.