The Sit On Air is a dynamic inflatable cushion which has a double use thanks to its wedge shape. When the straight edge faces the back of the chair, it helps maintain the correct posture as it activates the core muscles sustaining the spine. When it faces the front of the chair, it allows the legs to be slightly lifted in a relaxed sitting position. This device mimics the dynamic seating motion of an exercise ball and provides the same beneficial effects. Through inflation, you can easily adjust the stability level of your seat.