This article is about the All-New SimpliSafe system. If you purchased a system in 2017 or earlier, you have the Original SimpliSafe. We no longer offer CO Detectors for the Original SimpliSafe system, but you can contact support to find out how you can upgrade your system. If you're not certain which system you have, you can tell the difference here.
The following video walks through installing your Carbon Monoxide Detector. If you are trying to add a new sensor to an existing system, please see this page.