How long will the battery last in my First Alert Onelink combination Smart Smoke and Carbon Monoxide alarm?

The Onelink alarms are equipped with a 10 year sealed battery which will last up to 10 years – the life of the alarm. Please note that actual battery service life depends on the Smoke/CO Alarm and the environment in which it is installed. Regardless of the manufacturer’s suggested battery life, you MUST replace the Alarm immediately once the unit starts “chirping” (the “low battery warning”).