Tenergy 9V NiMH Battery, High Capacity 250mAh Rechargeable 9 Volt Batteries for Smoke Detector/Alarms, TENS Unit, Metal Detector, and More (4 Pack) : Amazon.ca: Electronics
Kidde Smoke Detector, 9-Volt Battery Operated, Ionization Smoke Alarm, Battery Included - Fire Alarm Battery Operated - Amazon.com
ANSMANN Smoke Detector Battery Replacement [Pack of 2] Square 9V E-Block Batteries For Smoke / Fire Alarm Replacements With 7 Years Life Time, Red: Amazon.co.uk: Electronics & Photo
Duracell 9V batteries - Smoke alarm batteries
Kidde Firex Smoke Detector, Hardwired with 9-Volt Battery Backup, Smoke Alarm, 6-Pack 21005927 - The Home Depot
Kidde Fire Sentry Micro Profile 3 Year Smoke Alarm, 9 Volt Battery - Walmart.com