The FireAngel W1-R series of alarms are available as either a heat or optical smoke alarm, both of which are mains powered with a replaceable 9V back-up battery. Both alarms feature a large, central silence button which also acts as a test button the SW1-R optical smoke alarm while the HW1-R heat alarm has a separate button for testing. Up to 12 W1-R and W1-PF series alarms can be interlinked together via a dedicated cable, including the CW1-PF-T mains powered carbon monoxide alarm, to provide full coverage and reliable warning of possible danger throughout the premises. These alarms also feature a ‘safety clip’ which prevents them from being installed without a battery, to ensure there is a back-up in case of a mains power failure.