What is the difference between the Onelink Smoke + CO and the Onelink Safe & Sound?

The Onelink Smoke + CO alarm is a wireless alarm that detects smoke/CO and notifies you via a push notification on your phone, in addition to a loud piercing sound in your home. The Onelink Safe & Sound is a smoke and carbon monoxide (CO) alarm that notifies you via a push notification on your phone, in addition to a loud piercing sound in your home. It also acts as a superior home speaker and has Amazon Alexa built-in. You can use it in your everyday life, from playing music to asking questions with simple hands-free commands, and rest easy knowing it will alert you at home and away in the event of an emergency.