Nest Protect 2nd Gen Hardwired Smoke and Carbon Monoxide Alarm, Wired 2PK - Newegg.com
Google Hardwired Smart Combination Smoke and Carbon Monoxide Detector with Voice Alert in the Combination Smoke & Carbon Monoxide Detectors department at Lowes.com
Google Nest Protect Smoke Alarm and Carbon Monoxide Detector, 2-pack | Costco
Google Nest Protect - Smoke Alarm - Smoke Detector and Carbon Monoxide Detector - Wired, White - Amazon.com