Highly Accurate: This alcohol tester uses a precise semiconductor alcohol sensor that reacts and recovers quickly, providing professional accuracy. One-Button Operation: Open the dust cover and wait 10 seconds to warm up, then blow into the mouthpiece for 10 seconds. The BAC result will be displayed on the LCD screen. PORTABLE DESIGN: The portable breathalyzer takes up minimal space and can be easily carried anywhere in your purse or pocket, measuring just 3.98 x 1.06 x 0.05 inches. Quick Troubleshooting Without Blowing into a Tube: Exhaled air captures the alcohol. Since alcohol is heavier than air, the alcohol sinks downwards, and detection without blowing into a tube is more accurate. Avoid bacterial growth in the mouthpiece. AUTOMATIC SHUT-OFF: The rechargeable breathalyzer automatically shuts off 10 seconds after the test is complete to save power. It alerts you with a beep. Easy to Use: Open the dust cover and wait 10 seconds to warm up, then blow into the mouthpiece for 10 seconds. The BAC result will be displayed on the LCD screen. How to use (instructions in English only): 1. Open the dust cover 2. The warm-up mode counts down for 10 seconds. 3. When the warm-up mode is complete, the test mode counts down from 10 to 00, during which time you blow in air. 4. After taking a deep breath, blow into the mouthpiece with normal force for 10 seconds. 5. Read the test result on the breathalyzer's display.