First Alert BRK SC-9120B Hardwired Smoke and Carbon Monoxide (CO) Detector with Battery Backup 4.6 out of 5 stars 3,869 6 offers from$56.24 #10 Kidde Hardwired Smoke & Carbon Monoxide Detector, AA Battery Backup, Voice Alerts, Interconnectable, LED Warning Light Indicators, 2 Pack ...
First Alert SMI100-AC, 9120B Replacement Hardwire Interconnect Smoke Alarm with Battery Backup, 1-Pack 4.6 out of 5 stars 5,822 13 offers from$18.34 #16 X-Sense Smoke Detector Carbon Monoxide Detector Combo, 10-Year Battery Smoke Detector with Display, Standalone Model SC01, Single Pack ...