How do I determine if my carbon monoxide non-digital alarm has reached its End of Life?

When the CO alarm emits a quick beep every 30 seconds and the red LED flashes, you may need to change the batteries. Once you have replaced the batteries, if the alarm continues to emits a quick beep every 30 seconds and the red LED flashes, the alarm has reached the end-of-life. When an alarm has reached the end of its life, it needs to be replaced to continue protecting your home.