This Harmony ZB, single light block for test light function has 1 connecting wire. It is supplied with 12V AC/DC. It is compatible with Harmony XB4 and XB5. This single light block allows fast and easy replacement and configuration of your signaling units for light testing purpose. It protects operators from unexpected contact with live circuits thanks to its IP20 protection index. Its wide range of operating temperatures from -25°C to 70°C allows versatility in usage of product.