The smoke “sensor” component is attached magnetically to the microwave. The microwave plugs into Safe T Sensor’s “control box”, which is then plugged into the wall outlet. The solution is simple, seamless and requires no change to cooking behavior. Shuts off power to the microwave as soon as smoke is detected. Note: This product is NOT recommended for use on microwaves with a dial-timer or on built-in microwaves (unless the exhaust vents are exposed).