The Nittan EV-SDR Base F16-82100 is a low profile Base Sounder. The EV-SDR Base is suitable for ceiling mounting and can be used with all types of Evolution analogue addressable detectors. The EV-SDR Base has 12 tone options (3 approved), which are selectable via DIP switch settings. The EV-SDR Base can be set to Activate with Detector, in the Panel configuration, without any special device setting.