Flexible vinyl compositions are plasticized primarily with general purpose phthalates. These plasticizers provide an adequate economic balance of processing and performance. However, in some instances general purpose phthalates can not deliver the performance or processability required for some specific applications. When this is so specialty plasticizers can be used to adjust the performance as required. Basic definitions of what are specialty plasticizers are, the classes of compounds used and why they are used will be presented and discussed. High solvator type plasticizers are generally used to improve the fusion characteristics of vinyl compounds or speed production with or instead of general purpose. The focus of this presentation will be high solvators. Specifically how solvator class is defined by laboratory techniques and how this information can be used in production. Other specialties will also be mentioned as to their purpose in vinyl compositions and how one considers them in formulation.