Features: Sensitivity/Alarm Time: Within 60-90 minutes at 50 ppm CO concentration; Within 10-40 minutes at 100 ppm CO concentration; Within 3 minutes at 300 ppm CO concentration LCD Display (optional): 4-digit LCD display Audibility: 85 dB (at 1 m distance), Frequency 3 - 0.5 kHz Standby Current: