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 testing with a range of 0.00% to 1.9% BAC or 0.0 to 1.9 g/L. Ideal for personal use by drivers. Simple to operate: Insert two AAA batteries (not included), power on the device, allow 10 seconds for warm-up, then breathe into the unit steadily for 3 to 6 seconds. Results appear on the LCD screen and remain visible for 10 seconds before the device automatically powers off. Built-in alarm function: If the result exceeds 0.05% BAC, 0.50 g/L, 0.25 mg/L, or 50 mg/100 mL, the device emits a continuous ble alert to warn the user against driving. For best results, wait at least 20 minutes after consuming alcohol before testing. Compact and portable design allows for easy carrying in a pocket or bag. Suitable for use at social events such as weddings, parties, and celebrations to help assess driving readiness.