Bonnell Coil System – Includes a 660 high tempered coil system. With 1-inch foam supports on top/bottom. Butterfly Edge Guard – 4-mm diameter butterfly edge guard for added edge/sitting support, with a ¼-inch quilted border. Euro Top Comfort – 4-inch ultra-soft memory foam and latex blends with double fiber pad for added lumbar support. Viscose Fabric Top – Stretchable viscose fabric for ultra-soft comfort feel.