With this digital breath alcohol tester, promptly and conveniently design for measuring BAC, a simple method to analyze blood alcohol concentration at any time and anywhere.How to Use Breath Alcohol Tester:1. Press and hold the power button for 1 second, the alcohol tester LCD with turn on with one beep sound.2. Warm-up mode countdown for 10 seconds.3. Testing mode countdown from 10 to 00 after warm-up mode, blow at this period.4. Blow into the breath inhaler for 3-5 seconds with normal power after a deep inhalation.5. Read the test result from the alcohol tester LCD.6. The ¡°Caution¡± symbol is displayed at: 0.020%BAC to 0.50%BAC(0.2g/l to 0.5g/l)7. The ¡°Danger¡± symbol is displayed with a beep audible alert at: over or equal 0.050%BAC(0.5g/l£Features: 1. High Accuracy Breath Alcohol Tester. 2. Energy-Saving and Auto-off. 3. Portable Designed Breathalyzer 4. Pre-cut individually to stick anywhere you'd like. 5. 5 Mouthpieces for Replace Specification: Color£ºBlackItem Dimensions LxWxH: 2.2 x 3.03 x 0.55 inches 2 x AAA batteries( not included)Notes:1. The first use of the tester or after a long time no use, press the power button and retry several times if possible.2. Repeatedly 2 or 3 times to obtain more accurate results.3. Do not smoke and eat for 20 minutes prior to testing.4. The test result is for reference only.5. Powered by 2pcs AAA alkaline battery(not included), replace the battery when the LCD screen flashes for low power.6. Detection range: 0.000~0.199%BACPackage Includes:Breath Alcohol Tester x 1Replacement Mouthpiece x 5