The 2GIG �Smoke Ring� Smoke Detector Sensor/Transmitter is the ideal solution to make homes even more safe & secure. The 2GIG Smoke Detector Sensor/Transmitter (aka �Smoke Ring�) works in conjunction with traditional ACpowered interconnected smoke detectors to communicate alerts to 2GIG (or other 345 MHz) alarm systems. The 2GIG �Smoke Ring� installs discreetly between the existing AC-powered smoke detector and the ceiling, providing a clean, unobtrusive solution. Utilizing the same AC line current that powers the smoke detector, the 2GIG �Smoke Ring� will always be �on� and, with a 7+ day battery backup, will even operate during a power outage.