I have a 16" sports wheelchair. I assumed this would work. Wrong. The seat is slung between the back tires, which cantilever a bit, to give better stability on the basketball court. Place a 4"x16"x18" cushion on my wheelchair seat and you sit too high. The cushion impedes the movement of those tires. tried it on my office chair as well. It's too high and hard to keep in the seat. Regreattably, I will return this item. It might be great for a heavier person with a standard size wheelchair. It just doesn't work for me.