High precision digital breath analyzer: This alcohol tester features a high-precision semiconductor alcohol sensor that quickly delivers results to help determine fitness to drive. Accurate test results up to 99.1%, with a detection range of 0.00% to 1.9% BAC or 0.0 to 1.9 g/L. Ideal for personal use by drivers. Easy to use: Insert 2 AAA batteries (not included), power on the device, and allow 10 seconds for warm-up. Blow steadily into the device for 3 to 6 seconds. Results are displayed on the LCD screen and remain visible for 10 seconds before the unit automatically powers off. Auto alarm function: If the test result exceeds 0.05% BAC, 0.25 mg/L, or 50 mg/100ml, the device emits a continuous audible alert to warn the user against driving. For more accurate results, wait at least 20 minutes after consuming alcohol before testing. Lightweight and portable: The compact design allows the breathalyzer to be easily carried in a pocket or bag. Suitable for use at weddings, parties, celebrations, and other social events to help assess driving readiness. Note: This alcohol tester includes 12 reusable, interchangeable mouthpieces for improved hygiene. Mouthpieces can be cleaned and reused as needed.