The VPC storage car is designed to hang 10" - 12" below the mast car via a wire or rope "tail". It is then hauled up and down the track in tandem with the mast car. As the pole comes vertical, the VPC car's chock engages the pole at the inboard end and prevents it from rattling, vibrating and binding. All four cars fit 1-1/4" T-Track. Select the model that matches your pole diameter or outer pole diameter if an expandable pole.