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 up to 99.1%, with a detection range of 0.00% - 1.9% BAC / 0.0 - 1.9 g/L. Ideal for personal use by drivers. Easy to operate: Insert 2 AAA batteries (not included), power on the device, wait 10 seconds for warm-up, then blow steadily for 36 seconds. Results appear on the LCD screen and remain visible for 10 seconds before the unit automatically powers off. Auto alarm function: If the result exceeds 0.05% BAC or 0.25 mg/L, the device emits a continuous beep to alert the user. For best results, wait at least 20 minutes after drinking before testing. Lightweight and portable design allows for convenient carrying in a pocket or bag. Suitable for use at weddings, parties, celebrations, and other social events to assist in making responsible decisions about driving.