This Technical Specification describes methods for the characterization of mesoscopic shape factors of multiwall carbon nanotubes (MWCNTs). Techniques employed include scanning electron microscopy (SEM), transmission electron microscopy (TEM), viscometry, and light scattering analysis.This Technical Specification also includes additional terms needed to define the characterization of scattered bending persistence length (SBPL). Two approximation methods are given for the evaluation of SBPL (which generally varies from several tens of nanometers to several hundred micrometers).Well-established concepts and mathematical expressions, analogous to polymer physi