4-Inch 5-Zone Orthopedic Foam Mattress Topper (King). Sleep blissfully every night on this orthopedic foam mattress topper. This mattress topper features five comfort zones to provide the right support for each part of your body, and the 4-inch thickness gives you a soft sleeping surface. Odor neutralization adds to your comfort level as you sleep. Twin: 4 inches high x 37 inches wide x 73 inches long Twin XL: 4 inches high x 37 inches wide x 78 inches long Full: 4 inches high x 52 inches wide x 73 inches long Queen: 4 inches high x 58 inches wide x 78 inches long King: 4 inches high x 74 inches wide x 78 inches long California King: 4 inches high x 70 inches wide x 82 inches long Foam Tips: Arrives tightly packed in portable box for customer convenience. Remove from packaging within 72 hours to maximize foam expansion. You can sleep on it the same night it is unwrapped, however allow 48 hours to fully return to its original shape. Vacuum sealing sometimes traps odors. After unwrapping, air product for a few hours to eliminate trapped odors. Due to machine-cutting manufacturing processes, there may be slight variances in the dimensions of this product. Due to the nature of foam, the firmness level of similar products may produce different firmness results. Once opened this product is non-returnable.