Specification Sensor: Advanced Semiconductor Oxide Alcohol Sensor Measuring range: 0.00% - -0.19% BAC (0.0 - -1.9 g/l or 0.00 - -0.95 mg/l BRAC) Measurement accuracy: 0.01% BAC (0.1 g/l). Power: 2 X 1.5 v alkaline batteries (without batteries, you need to buy it yourself) Operating time: warm-up time: 10s, response time: 5 s Automatic shutdown: about 35 seconds. Dimensions: 95x36x18mm forewarned It is recommended to use an alcohol tester after 20 minutes of drinking. Because it takes about 20 minutes for the body to absorb alcohol from the digestive organs into the bloodstream. In addition, alcohol remaining in the mouth takes about 20 minutes to dissipate. To make the measurement more accurate, please do not perform a second test within 3 minutes. Please do not smoke or eat for 20 minutes before the test. Please do not test the alcohol tester directly with chemicals such as benzene, thinner or gasoline. Please do not blow liquid into the airway of the alcohol tester Please do not contact the alcohol tester with any irritating substances, such as pain meters, pesticides, alcoholic beverages, etc. Please do not place the alcohol tester in an air-contaminated confined space. Modifying or replacing components of the internal unit may cause the tester to malfunction This paragraph is designed to help improve safe driving and cannot be used as a basis for the use and operation of vehicles, machines, equipment, etc. The blood alcohol content and intoxication measures mentioned in this design are not derived from references provided by governments, medical institutions, agencies or individuals. Only take BAC as a reference, and the manufacturer does not assume any legal responsibility. Everyone's sensitivity to alcohol varies, and some people's testers may be based on less than the legal human alcohol limit.