Feature 1WORKING DETAILS: This carbon monoxide alarm is equipped with a CO sensor, which can quickly respond to the CO level and provide an immediate alarm of the CO level within the range of 0 to 999ppm. If the concentration exceeds 300 ppm, the carbon monoxide detector will respond within 3 minutes to ensure that your family is safe. 2LED DISPLAY: This CO alarm is designed with a blue backlit LED digital display, accurate, reliable and sensitive data display, convenient to monitor. 3EASY TO INSTALL: This alarm is small and compact in size, light in weight that you can quickly complete the installation and put the alarm into use. 4ABS MATERIAL: Made of premium ABS material, this CO sensor is wear resistant, impact resistant, ensures a long life span. 52PCS: There are 2 pieces alarms in the package that you can install them in different rooms and make measurement more accurately and timely!SpecificationItem Type: CO Alarm Application: AlarmProduct Size: Approx. 10 x 10 x 4cm / 3.9 x 3.9 x 1.6in Product Material: ABSBattery: 3 x AA batteries (not included)Detection Angle: 360 Working Voltage: 4.5 (V)Alarm Current: 15 (mA)Quiescent Current: 60 (uA)Working Temperature: - 20 to 50 ()Detection Distance: Approx. 5m / 16.4ftTransmission Frequency:433 (MHZ)Launch Distance: Approx. 10m / 32.8ftAction Distance: Approx. 10mm / 0.39inCommunication Mode: WirelessAlarm Mode: Sound and light, LED blue lightDetection Gas: Carbon monoxide (CO)Concentration Range: 0 to 999PPMAlarm Volume: Greater than or equal to 80dBAlarm Concentration: 150PPM alarm .wang-edit-text{ font-family:'Arial' !important; } .wang-edit-text table { border-top: 1px solid #000; border-left: 1px solid #000; } .wang-edit-text table td, .wang-edit-text table th { border-bottom: 1px solid #000; border-right: 1px solid #000; padding: 3px 5px; } .wang-edit-text table th { text-align: center; }Package List2 x Alarm2 x English Manual2 Bag of Screw