The Comfort Co Curve - Molded Contoured Cushion has a mild anti-thrust shelf that promotes stability and forward migration while the medial thigh separator promotes postural alignment. The high density is made of molded foam increases surfaces area reducing potential high pressure area. Ideal for use in the car, wheelchair, and on the go. Sizes: 16" x 16", 18" x 16", 18" x 18". Sold by the each.