Kidde Smoke & Carbon Monoxide Detector Combo, 10-Year Battery, Replacement Alert, 4 Pack

2-in-1 Detection – Smoke & carbon monoxide detector combo alerts you to both smoke & fire events as well as poisonous, CO gas in a single device
Photoelectric sensor detects visible fire particles associated with slow, smoldering fires, while the electrochemical sensor detects carbon monoxide
An 85-decibel alarm sounds & a red LED indicates the smoke detector is sensing smoke or fire