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The Alecto SA-33 protects your home in case of fire. The package consists of 6 smoke detectors that are immediately ready for use. Link the smoke detectors together wirelessly across distances of up to 60 meters via the connection frequency of 434MHz. Since they're interconnected, all of the smoke detectors will go off simultaneously if fire is detected. The alarm will then produce an audio signal of 85dB. If you'd prefer to install only 1 smoke detector, that's no problem at all. The smoke detectors run on batteries (included). When the batteries are empty, this is indicated by a signal. After you install the smoke detectors, test if they work properly by using the test button and reset the system, whenever necessary, with the reset button.