The SF154B Emergency Call Switch features a push button switch with DPDT (double-pole double-throw) contacts which are available via wire pigtail. The switch comes pre-wired with both normally open terminals available individually. The switch has a mechanical eye arrangement inside, which provides for positive indication of activation without the need for external power. The switch features push-on pushoff operation. The SF154B is designed as a single-gang (UL 94V-0) plastic panel that fits a standard single-gang electrical box.