High precision digital breath analyzer: This alcohol tester features a high-precision semiconductor alcohol sensor that quickly delivers accurate results to help determine fitness to drive. Measures BAC from 0.00% to 1.9% (0.0 to 1.9 g/L). Ideal for personal use by drivers.Easy to use: Simply insert 2 AAA batteries (not included), power on the device, and allow 10 seconds for warm-up. Blow steadily into the mouthpiece for 36 seconds. Results appear on the LCD screen within seconds, remain visible for 10 seconds, then the device automatically powers off.Auto alarm function: If the result exceeds 0.05% BAC (or 0.25 mg/L), the device emits a continuous audible alert to warn the user against driving. For best accuracy, wait at least 20 minutes after consuming alcohol before testing.Lightweight and portable: Compact design allows easy carrying in a pocket or bag. Suitable for use at parties, weddings, celebrations, and other social events to support responsible decision-making about driving.