Universal Security Instruments MICN109 3-in-1 Smoke, Carbon Monoxide and Natural Gas Alarm is a perfect for new or replacement Installations. This 120-Volt AC/DC Hardwired Combination alarm Protects against smoke & fire, carbon monoxide & natural gas. Microprocessor virtually eliminates false alarms from sources like every day cooking smoke and steamy showers. Interconnectable up to 24 compatible devices, the patented Quick Find® alarm location feature easily identifies first alarm to sound in an interconnected system. Product end-of-service life warning sounds when it is time to replace alarm. 4 LED"s to indicate power, smoke, CO and gas. For added security, tamper-resistant locking feature prevents unwanted battery or alarm removal. Replace battery without removing alarm from bracket. The 9-Volt alkaline battery (included) continues protection in the event of a power outage. The included universal mounting bracket fits any standard wiring junction box measuring up to four (4) inches. The quick connect wiring harness features longer 8-inch pigtail wires, pre-stripped for convenient installation. The larger mounting base covers drywall imperfections and old paint marks. The single silence/test button temporarily quiets nonemergency alarms and tests alarm functionality. The full-size plastic dust cover protects the alarm from dust, debris and painting during construction or home remodeling. MEETS INDUSTRY STANDARDS - Listed to UL Standards 2034, 217 and 1484 and California State Fire Marshal approved. 5-year limited warranty. Universal Security Instruments is always working to protect your family.