High precision digital breath analyzer: This alcohol tester features a high-precision semiconductor alcohol sensor that quickly provides results to help determine if it is safe to drive. Accurate testing range from 0.00% to 1.9% BAC or 0.0 to 1.9 g/L. Ideal for personal use by drivers.Easy to use: Simply insert 2 AAA batteries (not included), turn on the device, and wait 10 seconds for warm-up. Then blow steadily for 3 to 6 seconds. Results are displayed on the LCD screen within seconds and remain visible for 10 seconds before the device automatically powers off.Auto alarm function: If the test result exceeds 0.05% BAC, 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: This compact breathalyzer easily fits in a pocket or bag, making it convenient to carry. Suitable for use at weddings, parties, celebrations, and other social events to help assess fitness for driving.