Kidde Smoke and (CO) Carbon Monoxide Alarm Value Pack: * Smoke alarm has hush button * Warning chirp sounds when smoke alarm battery needs replacement * Utilizes state-of-the-art ionization sensor * Loud 85 decibel alarm alerts you of danger * Mounting bracket allows for fast and easy installation (mounting hardware included) * Smoke alarm requires one 9V alkaline (included) * CO alarm requires 3 AA batteries (included) * 3-year limited warranty