The high-precision digital respiratory analyzer adopts advanced semiconductor sensors to ensure accurate readings in a short period of time. When using the alcohol tester for the first time or if it has not been used for a long time, pressing the power button a few more times can remove excess gas inside the semiconductor sensor to ensure accurate readings. High sensitivity: When you complete the test for 5 seconds, let the alcohol tester automatically turn off to save power. Please test after drinking for at least 20 minutes, as it takes approximately 20 minutes for alcohol to be absorbed from the digestive tract into the bloodstream. If tested immediately, it can only reflect the alcohol concentration in the mouth, not the alcohol content in the blood. Equipped with a backlit LCD display screen, it makes nighttime display more convenient and provides you with professional accuracy for safe driving. The breath analyzer can be easily opened and tested in just a few seconds with just one click operation. The portable alcohol tester saves space, is lightweight, and is completely easy to carry. To obtain more accurate measurement readings: Do not smoke or eat for 20 minutes before the test. The testing time should be 3 minutes after the last test. Power: Use 2 "AAA" alkaline batteries (not included with this machine)