Where there's smoke, there's the potential for danger. Become aware of it and the potential for fire with the Medallion™ Series Smoke Detector with Transmitter. When the photocell detector senses the presence of smoke, the built-in transmitter broadcasts a signal to any Medallion™ Series Mini Receiver. Easy to install in any room, it is powered by a long-life, 3-volt lithium battery for round-the-clock, 24-hour protection.