A. Functional features: It has an advanced planar alcohol sensor with rapid response. Surface Mount Device (SMD) assembly is used for stable performance. It comes with a liquid crystal display for direct testing process. B. It is equipped with a digital liquid crystal display with blue backlight. The design is portable and fashionable. It may emit a sound alarm when it goes beyond the preset range. It has a self - testing function for sensor faults. C. It adopts an energy - saving design and has a low - voltage indication function. It is equipped with a digital liquid crystal display. D. It is a professional breath alcohol tester for safe driving. The mouthpiece may need to be pre - heated to a wide range within 10 seconds. Each time it operates, it might 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. E. (No mouthpiece is required, just blow for 3 - 5 seconds) The design is compact and lightweight. It can be easily put into a wallet or pocket and is convenient to use. F. Package contents: 1 alcohol tester. G. Power supply: 3 AAA alkaline batteries are required (the batteries need to be prepared by the user and are not included in the package).