Orca photoelectric smoke alarms provide effective detection for slow smouldering fires as well as fast flaming fires, giving you and your family an early warning and plenty of time to respond. These smoke alarms also significantly reduce nuisance alarms caused by cooking. Powered by a single 9 Volt battery. Ideal for bedrooms and hallways. Includes 3 x Orca smoke alarms, 3 x mounting plates, batteries, user instructions.