Specification  Audible Alarm  If the test result is <0.02% BAC (or 0.2 g / l), the alarm sounds a "di".  If the test result is within 0.02% BAC (or 0.2 g / L) - 0.05% BAC (or 0.5 g / L), the alarm will sound as "di di".  If the test result is ≥ 0.05% BAC (or 0.5 g / l), the alarm sounds as "di di di ..."  3 Modes  Green light - <0.02% BA  Yellow light - 0.02% BAC -0.05% BAC  Red ligh - ≥ 0.05% BAC     Unit: % BAC-US, g/l-EU  Sensor: High-precision semiconductor sensor  Detection range: 0.00-0.20% BAC / 0.0-2.0 g/l  Warm-up time: Within 10 seconds.  Blowing time: Within 10 seconds  Response time: Within 10 seconds         New Upgraded Mental Shell     Different from other breath tester with plastic shell on the market, Q91 breathalyzer's mental shell is made of aluminum alloy makes it more durable and drip-proof.                U-Shaped Fastening Clip                  Easy to install and take to use in the car at any time.