The present invention is directed to a system for converting between single flow and split flow evaporative light scattering detection devices for detecting samples in a mobile phase. The guide-eyes fitted device is guided during longitudinal displacements along the longitudinal direction of the needles and along respective transverse displacements by guides. A firing mechanism may also be provided to cause a projectile to be propelled through the body. Management of service elements andor service offerings is facilitated by a Service Development Tool.