Kidde Pro Series Hardwired Smoke Alarm

120 V Interconnectable – Will interconnect with up to 24 other devices (18 of which can be initiating). 9V Battery Backup (included) – Provides continuous protection even during power outages. Ionization Technology – may detect invisible fire particles (associated with flaming fires) sooner than photoelectric alarms. Test Feature – Simultaneously tests the unit’s electronics and verifies alarm operation. Meets the requirements of CAN/ULC-S531