The model P4010ACSO-WF is a Smoke/CO alarm with Wi-Fi capability. The primary function of the product is to detect Smoke and Carbon Monoxide in residential spaces and alarm accordingly. The Wi-Fi capability gives the product Smart Home functionality where the alarm notifications are received on internet enabled mobile devices. The model P4010ACS-WF is a Smoke alarm with Wi-Fi Capability. The primary function of the product is to detect Smoke in residential spaces and alarm accordingly. The Wi-Fi capability gives the product Smart Home functionality where the alarm notifications are received on internet enabled mobile devices.