Product Description
4-Wire Smoke Detector The 4-wire smoke detector is a device that detects the presence of smoke in your home. This device has four wires, two of which are connected to each other. One wire goes into the power supply and the other three go to the sensor. When smoke enters the sensor, it closes the circuit and triggers the alarm. The sensor can detect smoke from cigarettes, cigars, pipes, wood burning stoves, etc.