First Alert SA3210 Dual Sensor Smoke and Fire Alarm Help keep your family safe with this battery-operated smoke alarm; it requires no rewiring for installation and provides continuous monitoring even if there's a power failure The 10-year lithium-ion battery offers continuous power for the life of the alarm and provides continued monitoring even if there's a power failure Loud 85-decibel siren sounds to alert you to danger To ensure complete protection make sure to place one on each level of your home and in each bedroom Meets UL217 standards and complies with legislative requirements for 10-year battery-operated smoke alarms