High Precision Breathalyzer Sensor: You can get the precise blood alcohol concentration with the upgraded high-sensitivity semiconductor sensor in seconds. Breath alcohol tester with backlit LCD display for easy viewing of the test result at night. Intelligent alarm function: According to the different traffic laws in European countries, you can set the alarm value by yourself (0.20BAC / 0.30BAC / 0.50BAC / 0.80BAC). the buzzer sound prompt if your alcohol level exceeds the value you set. One Button To Test: Semiconductor Breathalyzer is easy to use. Simply insert the batteries 2x AA batteries are required (not included) and press the power button to start the test. 6 Replaceable Mouthpieces: This alcohol tester comes with 6 replaceable mouthpieces which can be cleaned and recycled. Alcohol tester is small enough to keep in your car, handbag, backpack or briefcase. Especially we have prepared a portable velvet bag in your car and a perfect gift for your friends. Product description Portable electronic breathalyzer with digital LCD screen. Operation steps: 1. After drinking and waiting 20 minutes, start drinking. test 2. Gargle with water or soft drink before testing 3.Install the 2*1.5V AAA battery (not included). < p class="a-spacing-base">4. Remove the mouthpiece from the back cover. 5.Install the mouthpiece.