The BRK Brands, Inc. model SC9120B is a wire-in, 120V AC 60Hz single and/ or multiple station smoke and CO alarm specifically designed for residential and institutional applications including sleeping rooms of hospitals, hotels, motels, dormitories and other multi-family dwellings as defined in standard NFPA 101. The SC9120B complies with UL217, UL2034, CSFM, NFPA 72, NFPA 720, HUD, FHA and other agencies that model their codes after the above agencies. They meet building codes where AC/DC with Silence smoke and CO alarms are required either separately or in combination. The alarms are interconnectable with up to 18 devices, of which 12 can be smoke alarms. The BRK® SC9120B alarm features a dual ionization smoke sensing chamber and an electrochemical carbon monoxide sensor, an 85dB horn and a silence? feature. Intelligent Sensing Technology? system is designed to reduce nuisance alarms. Latching Alarm Indication? remembers which unit initiated an alarm. When interconnected in a series, the unit that triggered the alarm rapidly flashes its red LED indicator. After the alarm condition subsides, the initiating unit will store in memory or latch? the information and begin to flash the LED indicator 2 seconds on, 2 seconds off. The Perfect Mount? system features a gasket less base and a mounting bracket that keeps the alarm secure over a wide rotation range to allow for true alignment. Other Contractor Preferred features include a dust cover to keep alarm clean during construction, keyhole slots in the mounting bracket eliminate the need to remove the electrical box screws for installation. Two locking features are provided to prevent battery theft and/or theft of the unit. Connection to AC power is made with a Quick-Connect? wiring harness. Installation is quick, easy and cost effective.