The mouth inflatable IndoFLO Balance Cushion is used as an alternative to the roller. You can adjust the degree of instability on the cushion with the level of inflation. Less inflation means more stability while inflating the cushion to it"s maximum creates the most instability. The basic difference between the Flo cushion and the roller configuration is that the deck does not actively roll on the cushion, it tilts around, offering a full circle of instability. This is a challenging, yet fun, way to ride the board and to try to stabilize it which creates the exercise.The IndoFLO Cushion is the perfect accessory for all Balance Trainer decks. The innovative concept is to provide a full circle of instability without the abrupt direction changes encountered with a roller. This virtually eliminates falls and offers a complete workout.The IndoFLO Balance Cushion creates a fluid transition with a totally unstable platform. The air cushion creates a free flowing instability that is challenging, fun and immediately beneficial in all aspects of core and balance training. Great for stand up paddle board training!