The USI Electric MDSCN111 4-in-1 Universal Smoke Sensing Smart Alarm provides quadruple the protection with a single installation. This 120-Volt AC alarm protects against (4) deadly household threats: fast-flaming fires, smoldering smoke, carbon monoxide and natural gas (or methane). Perfect for new or replacement installations, the MDSCN111 alarm is suitable for houses, apartments and mobile homes. Universal Smoke Sensing Technology (IoPhic) responds 87-percent faster to slow smoldering fires and responds quickest to fast-flaming fires. Auto sensitivity calibration provides superior nuisance alarm protection and creates consistency in alarm sensitivity. This alarm has additional automatic features including a self-diagnostics check to ensure proper operation, a sensitivity adjustment for changes in temperature or humidity and an end-of-service life warning that sounds when it's time to replace the battery. The 9-Volt alkaline battery (included) continues protection in the event of a power outage. This alarm features a front-loading battery drawer for replacing the battery without removing the alarm from the bracket. Mount the bracket to any standard wiring junction box and use the large mounting base to cover imperfections in drywall. For maximum protection, install an alarm inside every bedroom, outside every sleeping area and on all levels of the dwelling. The USI Electric MDSCN111 4-in-1 Universal Smoke Sensing Smart Alarm comes with a 7-year limited warranty. USI Electric is a subsidiary of Universal Security Instruments Inc., a U.S. based manufacturer of high quality, easy-to-install home safety products. Founded in 1969, Universal Security Instruments has over 40-years of heritage in providing home safety products for families. With state-of-the-art manufacturing facilities, Universal Security Instruments continues to launch revolutionary new products and technologies with the mission of always working to keep families protected.