At times Moog Music sold certain pre-packaged configurations of their modular synthesizers, with certain types and sizes of cabinetry. All of these were customizable by the customer, and it is likely that no two of a particular model actually left the factory with the exact same configuration. It was also possible for a customer to expand an existing synth by adding more cabinets. Nonetheless, the model designations served as a useful shorthand for the general size and scope of a particular unit.