Features: -Alarms about abnormal levels of carbon monoxide concentration with 4 red blinks and 4 loud beeps (every 5 seconds). Alarm is also reported to your iOS device. -Measures carbon monoxide concentration and reports. If measured value differs from preTechInfo: Power supply: 3.0V DC battery Battery type: CR123A Lifespan under typical conditions: 8 years CO concentration measurement range: 0 - 450 ppm Measuring accuracy: ±10ppm / ±5% Alarm response times: -50ppm 60-90min -100ppm 10-40min -300ppm Alarm siren sound level: 85 dBA at 3 meters (10 feet) Operating temperature: 0 - 50°C (32-122°F) Operating humidity: 10-95%RH without condensation EU directives compliance: -RED 2014/53/EU -RoHS 2011/65/EU -EN 50291-1:2010 Radio protocol: Bluetooth® low energy Radio frequency: 2.4 GHz Range: up to 50m (free range) (164 feet) Operating temperature: 0-50°C (32-104°F) Dimensions (diameter x height): 65 x 28 mm (2.56 x 1.1 inches) Warning: Using batteries other than specified may result in explosion. Dispose of properly, observing environmental protection rules.