If you have back problems you don’t want to be without this. This is the one product that has saved me from a lot of back pain and allowed me to continue to travel in spite of a disc problem. Our family has four of the 4” and two of the 2” and we can’t live without them. I use the 4” at home and work and the 2” in the car. I recommend the Sitts cushion to anyone who is dealing with back issues. They are very well made. If you have any questions the company is very responsive and helpful.