Feature: 1. One-button operation, automatic shutdown, very convenient to use. Just need three AAA batteries (not included) and you can start operation 2. The operation is simple, press the 1 button to enter preheating (20s), blowing, three modes will be displayed for you, easy to read 3. The test result will be displayed on the LCD screen for about 10 seconds, and the tester will automatically shut down. You can easily change the measurement unit and set the user-defined BAC test threshold. 4. With an advanced sensor, it can respond quickly, with power saving and low voltage indication functions. After the test, it will automatically sleep for 5 seconds 5. With LCD display and audio warning function, the product has a sensitive semiconductor sensor, when the content exceeds the preset limit value, it can easily display the degree of poisoning in the body in a few seconds, and provide the test result (0.01 mg / L ) Specification: Item Type: Digital Breath Tester Test Range: 0.000-0.199% BAC (000-199mg/m) Undervoltage Indication: Vcc <3.00V±0.1V displays undervoltage; Vcc <2.47V±0.1V undervoltage shutdown Accuracy: ±0.01%BAC Operating Time: Preheating for 100 seconds, response within 5 seconds Working Environment: -10℃-50℃ Display Mode: 3 digits with blue backlight and graphic display Battery: 3 x AAA alkaline batteries (the machine does not come with batteries) Product Size: Approx. 10.5 x 7.5 x 2.5cm / 4.1 x 3 x 1in. Package List: 1 x Tester20 x Mouthpieces1 x User Manual Note: 1. The test result is accurate after drinking for 20 minutes. A test performed immediately after drinking will only show the current content in the mouth. Please be patient 2. Please allow 0‑2 cm error due to manual measurement. Thanks for your understanding. 3. Monitors are not calibrated same, item color displayed in photos may be showing slightly different from the real object. Please take the real one as standard.