What essential tool must inspectors have to perform emissions tests?

An emissions analyzer is the essential tool that inspectors must have to perform emissions tests effectively. This device measures the concentration of certain harmful pollutants in the vehicle's exhaust gases, providing vital data needed to determine whether the vehicle meets the required emissions standards.

Using an emissions analyzer allows inspectors to assess the performance of the vehicle's emissions control systems accurately. It typically connects to the vehicle's exhaust system and may use various technologies to analyze exhaust composition, helping ensure compliance with environmental regulations. This tool is fundamental in maintaining air quality and emissions standards that protect public health.

The other tools mentioned may be useful in various aspects of vehicle testing or diagnostics, but they do not provide the specific functionalities required for performing comprehensive emissions tests.