?5 Interchangeable mouthpieces? There are five onboard mouthpieces on the back of the product. Don't have to worry about forgetting the mouthpiece when you're out. ?Easy to use? Just press the power button for 3-5 seconds to start the professional breathalyzer, wait 15 seconds to warm up, then blow for 5-6 seconds with the tester, the result will be ready after 3 seconds it will be displayed on LCD screen for 15 seconds (3 AAA batteries required - not included). ?High Accuracy? This alcohol tester has a high precision semiconductor alcohol sensor. It can provide quick result to judge whether you can drive or not (only 5 seconds). Bring solace in everyone, increase feeling joy happiness is our driving force. ?Loud alarm sounds? You will receive an alarm by emitting a tone if the result is greater than 0.050% BAC, 0.500 ? Bac or 0.250 mg/L (BAC). ?Portable design? This breathalyzer is easy to maintain to carry. white pouch provides great convenience so that you can take it with you anywhere, anytime ensures you a safe ride after driving.