This AC wired-in smoke, CO, and natural gas detector interconnects with up to 24 compatible devices to provide complete protection inside any structure. It's listed to UL2034 standards.^^FeaturesIonization SensorMicroprocessorVirtually Eliminates Nuisance AlarmsEnd-of-Life WarningTest/Reset ButtonQuick Draw Battery Drawer4 LED IndicatorsPower, Smoke, CO, and GasTamper-Resistant Locking FeatureBattery Activation Pull Tab9V Heavy-Duty Battery (included)Loud 85 dB Alarm^^Warranty Information^This smoke, CO, and natural gas detector comes with a limited warranty. The warranty is good for 7 years.