ER/Studio comes in two editions:
ER/Studio Standard
Provides complete environment for analyzing, designing, creating, and maintaining database applications; no team collaboration capabilities or connection to the repository.
ER/Studio Enterprise
Provides complete environment for analyzing, designing, creating, and maintaining database applications; enables improved collaboration through a scaleable, server-side model management system for versioning, security, and component sharing, includes ER/Repository and one seat of ER/Studio Standard. ER/Repository distributes work across modeling team members in a safe, controlled way, facilitating a collaborative modeling environment for ER/Studio users and increasing productivity out of the box. The secure, scalable environment is fully integrated with the current, natural workflow in ER/Studio.
ER/Studio Viewer
ER/Studio Viewer is an optional stand-alone application that provides an interactive environment for viewing ER/Studio data models. This distributable application features the same sophisticated and advanced viewing, navigation and printing functionality offered to modelers themselves through the native ER/Studio application.