USI Electric 5304L Hardwired Ionization Smoke and Fire Alarm with Battery Backup Ionization smoke and fire alarm responds quickly to fast-flaming fires to protect your family against deadly threats in the home Features a single silence/test button to temporarily quiet a non-hazardous alarm and an audible low battery indicator that sounds for up to 30 days (2) tamper resistant locking features prevent unauthorized removal of the alarm or battery The 10 year lithium battery backup (included) provides protection in the event of a power outage for the entire life of the alarm. Comes with a 3 year limited warranty