This smoke alarm provides continuous protection against smoke and fire hazards even during power outages. The dual ionization and photoelectric sensors offer the best protection against both fast flaming and slow smoldering fires. Smoke alarm comes complete with a Hush® feature which temporarily silences the alarm, a low battery warning and a loud 85 dB alarm, a test/reset button and a red LED light which flashes every 30-40 seconds to indicate that the smoke alarm is operating properly.