2 x Home Fire Alarm Smoke Detector Gas Sensor Fireangel Twin Pack with Batteries Optical smoke sensing technology detects slow smouldering fire Resistant to nuisance alarms Ideal for grade F installations where cost is a priority Large central test and silence button feature Product life span: 10 year. Battery life: 2 x 1.5 V AA (replaceable battery Included) replaceable battery Included Sounds a loud 85 dB alarm Certified to BS EN 14604: 2005 Can be used in the bedroom, living room and landing Note: If the item stops working or goes on and off please replace the batteries Package Included 2 x Alarms 1 x Roll Of Double-sided Hinsinc 2 x Home Fire Alarm Smoke Detector Gas Sensor Fireangel Twin Pack with Batteries in White