TOGU 30-4231G Dynair Senso Cushion, X-Large, 4" Height, 14" Width, 14" Length, Green

This may be useful as a tool for some physical exercise for those with back pain. I bought this product with an intention to use as a cushion on my office chair, but this is not designed comfortable at all. There's no way you can rest your bottom nice and snug on this, but you have to constantly move and adjust your bottom position to maintain balance as if you are sitting on a fitness ball.