The Aico Ei168RC Easi-fit RadioLINK Base is a mains-powered unit with a built-in tamperproof rechargeable lithium back-up battery. It enables wireless RadioLINK interconnection between alarms, allowing all alarms in the system to sound when one is triggered. This base is compatible with Aico 140 and 160RC series alarms, and up to 20 units can be fitted on one system. The built-in RadioLINK provides wireless interconnection between alarms. It is mains powered with a rechargeable lithium cell back-up.