The Wurlitzer style 17 PianOrchestra is the last model manufactured and offered for sale that still used the earliest PianOrchestra tracker-bar layout. These early machines had a model number, but no other kind of classification, other then "The PianOrchestra." Then, when the  Mandolin and Concert series PianOrchestras were introduced, the old style machines were referred to as a "Regular" PianOrchestras. Thus, the Style 17 is the last of the "Regular" style PianOrchestras.