Wire-in, 120V AC 60 Hz single or multiple station smoke 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 101Complies with CAN/ULC S531Meets building codes where AC and AC/DC with Silence smoke alarms are requiredAlarms are interconnectable with up to 18 devices, of which 12 can be smoke alarmsFeatures a dual ionization smoke sensing chamber screened for insect protection, an 85dB horn, and a "silence" featureThe "Smart Technology" system is designed to reduce nuisance alarmsFeatures a gasketless base and a mounting bracket that keeps the alarm secure over a wide rotation range to allow for true alignment