Aico 600 Optical Smoke Alarm is powered by a 9V Alkaline battery and contains a large, proven optical smoke chamber and is best for detecting slow, smouldering fires commonly produced by electrical fires or sofas and is less likely to react to cooking smells if fitted in the hallway next to the kitchen. RadioLINK wireless interconnection technology is built in to this alarm. RadioLINK uses Radio Frequency signals to link alarms together. All RadioLINK alarms and devices should be House-Coded together upon install. As this alarm contains a 9V Alkaline battery, we recommend you replace the battery every 12 months to ensure contained protection. We also have an RadioLINK+ Battery Optical Alarm with a 10 year life, sealed in lithium cell providing the same level of protection, but without the need to replace the battery.