Function:
1) Three LEDs indicates the different status: Red LED for alarm; Green LED for low power to remind the replacement of battery; Yellow for circuit failure.
2) Test/Hush button: The test/hush button will stop alarm for about 5 minutes, after 5 minutes the concentration is more than 150ppm, it will re-alarm in 2 minutes.

Specification:
1) Power: DC 9V battery operated
2) Alarm sensitivity: Conform with EN50291standard
3) Standby current: <30µ A
4) Alarm current: <30mA
5) Operation ambient condition: 4~38º C, 25~85%R. H.
6) Sensor type: Electrochemical
7) ALARM VOLUME: ≥ 85dB at 100cm @3.4± 0.5KHz pulsing alarm (The alarm sound pattern: BI 4 times - pause 1.5s — BI 4 times, with a corresponding LED flash, repeat this alarm pattern)