This Harmony XB4, light block with body/fixing collar isoperates with BA9s bulb.It has 1 x NO 1 x NC contacts and a metal body and is compatible with Harmony XB4 pilot lights.This light block allows fast and easy replacement and configuration of your signaling units.It is easily installed and replaced on compatible illuminated push button or selector switch units via clip together assembly and connected with simple screw-clamp connections.It enables visual distinction of signaling units via illumination by connected with BA9s bulb.It protects operators from unexpected contact with live circuits thanks to its IP20 protection index.It is designed to fit with a standard 22mm control and signaling units, ensuring compatibility when installing in pre-existing machinery.Its wide range of operating temperatures from -40°C to 55°C allows versatility in usage of product.