The Universal Security Instruments hardwired MIC1509S 3-in-1 Smoke, Fire and Carbon Monoxide Smart Alarm provides 10 years of continuous protection against deadly threats in the home. Patented Universal Smoke Sensing Technology USST provides the benefits of both photoelectric and ionization alarms in one device to protect against fast flaming and slow smoldering fires. This alarm also features protection against the silent killer - carbon monoxide - making it a 3-in-1 device. Perfect for new or replacement installations, this maintenence-free alarm is suitable for houses, apartments and mobile homes in every room. The sealed back-up battery (included) will never have to be replaced throughout the life of the alarm, giving you a decade of peace of mind even in the event of a power outage. Permanent Power battery backup also saves money from battery replacements (up to $38.00 over the 10-year life of the alarm), eliminates annoying low battery chirps and helps the environment by reducing environmental waste from disposed batteries. This alarm features microprocessor intelligence to completely eliminate nuisance alarms, a single silence/test button to quiet a non-hazardous alarm and an end-of-service life warning that sounds when it's time to replace the alarm (approximately 10-yearsnt of existing Universal Electric alarms, this alarm features a large mounting base to cover imperfections in drywall and the option to replace retrofitting applications. The quick activation battery pull tab makes it easy to install while the deactivation key switches the alarm off and makes the alarm safe for disposal. Once the alarm is deactivated, the tamper resistant feature turns on to prevent deactivated alarms from being reinstalled. This alarm conforms to UL217 and UL2034 standards, California State Fire Marshal approved and Federal Housing Authority (FHA) approved to exceed industry standards.