This blue light block with integral LED allows fast and easy replacement and configuration of your signaling units. It is supplied with 24V AC/DC and it connects with simple screw-clamp connections. It is easily installed on compatible illuminated push button or selector switch units via clip together assembly. It is compatible with Harmony XB5 diameter 22mm control and signaling units. It enables visual distinction of signaling units via illumination by integral LED. It protects operators from unexpected contact with live circuits thanks to its IP20 protection index.