Online light scattering detectors and viscometers provide information about the polymer structure. If a light scattering detector is used together with an RI, then it is not necessary the use of polymer standards to calibrate the equipment, since light scattering gives the absolute weight- average MW (Mw). Light scattering detectors also measure the radius of gyration. Viscometer detectors also provide information about the intrinsic viscosity of the polymer and the level of branching (index of branching) of the polymeric chains. The more the number of detectors coupled to the GPC equipment, the more detailed is the structural and chemical information of a polymer that can be obtained.