Universal Security Instruments MDS300-401 4-in-1 Universal Smoke Sensing (IoPhic) Smoke and Fire Alarm with CO and Natural Gas Alarm Universal Smoke Sensing Technology responds quickly to both fast-flaming and slow-smoldering fires 9-Volt alkaline battery (included) operates the alarm and continues protection in the event of a power outage Responds 87-percent faster to slow smoldering fires and responds quickest to fast flaming fires Features a quick activation pull-tab and front-loading battery drawer for replacement without removing the alarm Comes with a 10 year limited warranty