Selling this as I no longer need it (having switched away from gas). FireAngel W2-CO-10XQ Wi-Safe 2, 10 Year Battery CO Alarm Advanced electrochemical sensor designed to accurately measure low levels of CO Wi-fi-safe 2 - Wirelessly interlink up to 50 alarms. If one alarm goes off They all go off Led status indicators for power and alarm mode Locate feature - silence all but initiating alarm in network Product life span: 10 year. Battery life: 10 year sealed for life Battery [Note: now 4 years left on the battery] Certified to BS EN14604: 2005 and lpcb approved
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