The Intoxilyzer® 400PA operates in up to three modes—Precursory, Analyze, or Precursory/Analyze. If the optional printer is attached, results are automatically printed in the Analyze mode. Precursory mode allows for mass screening of subjects without the need for disposable mouthpieces. Analyze mode requires the use of a disposable mouthpiece, and gives an exact reading of the breath alcohol concentration. In the third mode, Precursory/Analyze, if the precursory test is above a preset limit, the instrument automatically enters the Analyze mode for a precise reading. The 400 PA is also available in “Pass, Warn, Fail” mode, and can be configured at the factory to the customer’s specific requirements—the 400PA lets you design your instrument to meet your needs.