Tri-Zone Pocket Coil System – Includes 3 zones of support at 1322 high tempered coils (head/torso/foot) with thick 2-mm spring coils for extra lumbar support in the torso zone. Complete with 1-inch foam support at the bottom for additional mattress integrity. Foam Encased Edge Guard – 4-inch hard foam perimeter for added edge/sitting support, with a ¼-inch quilted border. Pillow Top Comfort – 4-inch medium soft foam layered with 2-cm gel foam and double fiber pad for added lumbar support. Viscose Fabric Top – Stretchable, embossed viscose fabric for additional soft comfort feel.