There are some errors with your dimensions:
Add a layer of polyester fibre to your foam for extra comfort, you can choose from three sizes 4oz, 9oz and 14oz. A stockinette cover will also be put on for ease of getting the foam in and out of a cover.
Add this option if you'd like to give your cushion an extra plump look, this option is also advisable when replacing feather or fibre cushion inserts.