The Hella RTK-QS opens a new dimension in optical-acoustical warning systems. The roof-mounted device has been developed for medium-size to large fire department vehicles. The light bar, with its modern as well as aerodynamic and especially flat design, houses a highly modular system, allowing for several thousand configuration options. The combination of various device lengths with different electronic, lighting, and acoustic modules are only some of many different equipment options. The optional lighting modules include, for example, side-mounted work lamps, which fit into the system contour and can be adjusted according to the vehicle type. The silver aluminium hole-panel is colour-adapted to the flexible carrier system; it ensures a harmonious appearance as well as the best signalling effect of the acoustic system located behind it.