1. Functional features: Advanced planar alcohol sensor with rapid response. Surface Mount Device (SMD) assembly is adopted for stable performance. It has a liquid crystal display for direct testing process. 2. It is equipped with a digital liquid crystal display with blue backlight. The design is portable and fashionable. It will emit a sound alarm when it exceeds the preset range. It has a self - testing function for sensor faults. 3. It adopts an energy - saving design and has a low - voltage indication function. It is equipped with a digital liquid crystal display. 4. It is a professional breath alcohol tester, an alcohol tester for safe driving. The mouthpiece needs to be pre - heated to a wide range within 10 seconds. Each time it works, it will automatically alarm if it exceeds the preset limit and has a digital output. It adopts an energy - saving design, has a low - battery alarm and comes with instructions. 5. (No mouthpiece is required, just blow for 3 - 5 seconds) It is compact and lightweight in design, can be easily put into a wallet or pocket, and is convenient to use. 6. Package contents: 1 alcohol tester. 7. Power supply: 3 AAA alkaline batteries are required (the batteries need to be prepared by yourself and are not included in the package).