A spray-gun line-connecting device is provided for the connection of a plurality of lines between a robotic arm and a spray device. The spray-gun line-connecting device may provide a plurality of cylindrical connection joints at an interface between mating surfaces. For example, the lines may include enlarged cylindrical heads, which fit within cylindrical receptacles in a first mating surface. A second mating surface may extend over the first mating surface, and include passages aligned with the lines.