The Trainer+ Base attachment is compatible with the Vertec Head Frame and the Trainer+ attachments. The Trainer+ base may be attached to the small ring, large ring, u-shaped attachment and Vertec™ head frame attachment for endless training possibilities. The Trainer+ base was designed for stability, strength, and ease of mobility. The wheels at the base of the Trainer+ allow coaches and players to maneuver the Trainer+ through different drills. Find the full Trainer+ package here.