Backlit display screen: Blue backlit LCD display, the numbers are clear and easy to read, and you can see clearly at night. Three unit conversion: %BAC / BAC / mg/L three alcohol measurement units can be converted. Easy to use: Simply press the power switch for 3-5 seconds to start the professional breathalyzer, wait 15 seconds to warm up, then blow with the tester for 5-6 seconds, the result will come out after 3 seconds and be displayed on the LCD screen for 15 seconds. 20 Interchangeable Mouthpieces: This breathalyzer comes with 20 interchangeable Mouthpieces, you don't have to worry about forgetting to bring Mouthpieces when you are out and about. Portable Design: This breathalyzer is easy to hold and carry, and the white cloth pouch provides enough convenience that you can take it with you anytime and anywhere to ensure safe driving after drinking. Specifications: Color: black Material:ABS Test range: 0.000-0.199%BAC;0.000-1.990BAC;0.000-0.995mg\L Alarm point: 0.050%BAC;0.500BAC;0.25mg\L(BrAC) Accuracy: 0.010%BAC;0.10BAC;0.05mg\L Reaction time: lt;5 seconds Preheating time: 15 seconds Working voltage: 3#AAA battery (not included) Working environment: 5-40 Product size: 11.2 * 6.1 * 2.9cm Product weight: 69g Package size: 16.5 * 11.8 * 4.5cm Package weight: 196g Package List: 1 * Alcohol Tester 20 * Mouthpieces 1 * Cloth Pouch 1 * User Manual