The Ei 650 runs on a 9V battery and lasts up to 10 years. Since the smoke detector doesn't run on AC power, you can place it wherever you like. When the detector detects smoke, it produces an 85-decibel audio signal. Place a smoke detector on every floor so you can be sure you're well protected. Use the test button regularly to check if the smoke detector is still working. That way, you
can be sure it's still doing its job.