Circular Light Rings provide a visual target and notify the user when to start and stop blowing. Internal Dual Flow Tube allows subjects to blow without touching their lips to a mouthpiece. No more sharing contaminated tubes with multiple users or paying for replacement mouthpieces. Patent Pending BluFire Sensor Technology provides extremely accurate test results by steadying airflow and requiring a deep lung air sample for each test. Wide Test Range - Measures Blood Alcohol Content from 0.00 to 0.40%BAC. Inverse LCD Display - White digits on a black background make test results easy to view in daylight and at night. Recessed display helps prevent scratching. On-screen instructions guide users when to wait and when to blow. One Button Operation - Simply turn it on and begin testing in seconds. Tap-Proof Power Button - Prevents the BACTRACK B70 from accidentally turning on. Hold power for five seconds to display the total number of tests performed. Compact size and sleek design easily fits into a pocket or purse