High precision digital breath analyzer: This alcohol tester features a high-precision semiconductor alcohol sensor that quickly delivers 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 two AAA batteries (not included), turn on the device, and allow 10 seconds for warm-up. Blow steadily into the mouthpiece for 3 to 6 seconds. Results are displayed on the LCD screen within seconds and remain visible for 10 seconds before the unit automatically powers off. Auto alarm function: If the test result exceeds 0.05% BAC, the device will emit a continuous audible alert to warn the user against driving. This safety feature helps promote responsible decision-making. Lightweight and portable: The compact design allows the breathalyzer to be conveniently carried in a pocket or bag. Suitable for use at weddings, parties, celebrations, and other social gatherings to assist in determining fitness to drive. For more accurate results, wait at least 20 minutes after consuming alcohol before testing.