BACK WCTCA416 optical smoke detector with isolator shallow base CAST series WCTCA414 optical and thermal detector with isolator, shallow base CAST protocol WCTCA402 Thermal Detector with isolator shallow base CAST protocol WCTCA408 Base for CAST detectors WCTNCP27 Back box for ceiling mount in PVC for CAST protocol detectors WCTCA470 Manual call point for CAST protocol fire systems with isolator WCTCA47067 Manual call point (CAST protocol) for external use