The BRK Brands, Inc. model SC9120LBLA is a wire-in, 120 VAC 60Hz single and / ormultiple station smoke and carbon monoxide 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 Model SC9120LBLA complies with CAN/ULC S531. They meet building codes where AC/DC smoke and carbon monoxide alarms are required either separately or in combination.The alarms are interconnectable up to 18 devices, of which 12 can be smoke alarms.The BRK SC9120LBLA features a dual ionization smoke sensing chamber - screened for insect protection and a carbon monoxide sensor, an 85dB horn, 9V battery back-up and a “silence” feature. The “Intelligent SensingTechnology” 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 Red LED indicator 2 seconds on, 2 seconds off. The “Perfect Mount” system features a gasketless base and a mounting bracket that keeps the alarm secure over a wide rotation range to allow for true alignment. This will allow fine-tuning on the positioning to compensate for out of aligned wall studs and to keep the wording level when wall mounting. A Single button test/silence button eliminates confusion. Depending on what mode the alarm is in, pushing the button will test, silence, re-test the alarm when in silence and clear the latching feature. Battery installation and removal can occur while the unit is mounted to the ceiling or wall via the side load battery compartment. 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.