I spotted the Obus Forme back and seat rest at Walgreens and the manager gave it to me for free it. It keeps your posture in the correct position. You're not supposed to slouch first of all and it has velcro straps that keep it in place. I would have paid the $100 plus for this but turned out to be my lucky day. You might want to get the seat rest too.
The convex design is different than most support products on the market. I am glad that I purchased the large even though it is recommended for 6'2"plus sizes. This prevents you from slouching and keeps you sit up straight. It sure beats the back pain that I get from leaning back or slouching over in my chair too long.
I bought this back support for my office chair. It feels like a curved board with very soft cushion and strap on it. It also straighten up your position and gives you relief. This is a must have in the office.