The seat cushions are custom cut foam of the highest density available at my local foam shop. I brought a cardboard pattern of the seat pan to the shop and asked for a 9 inch thick cushion shaped like the pan. The seat back is 3 inches thick and 3 inches wider so that it wraps around the edges when pressure is applied. The foam shop wrapped them in Dacron for me and I had the covers made once the foam was available as a pattern.