Product configuration management is presented as a practical application for a prototype-based object model. Data model requirements for a configuration system are first introduced using a realistic example from industry. Problems with the traditional type-instance model in this application domain are then identified and given as motivation for the prototype approach. A prototype-based object model with inheritance tree transformations, constraints and component relationships is presented as a tool for expressing dynamic configuration data. Finally, a sample configuration process is described using the prototype object model.