This extra large cushion is 24 inches in diameter and inflates up to 12 inches high. Recommended inflation height is 5 to 9 inches depending on your chosen application. Uses include using it under any size surfboard without fins to get a balance workout by simply placing the board on top of the cushion and keeping the board from touching the ground. This is also an excellent Stand Up Paddle trainer for shops to demonstrate the instability encountered on SUP equipment as well as an at home SUP trainer.