15 hours supply of air during power failures! It’s the perfect aquarium backup. • Automatically switches to battery (DC) mode • Low noise, low vibration. • AC / DC powered. Functions as a normal air pump but automatically switches to DC mode during a power failure. • 15 hours of backup aeration. • Energy saving Pulsing Mode that further increases battery life. • Low noise, low vibration. • Increases oxygen levels in your aquarium.