Mattress, free-end coil construction. Firm support. Non-sag edges. No side sway. Inner support. Felt-padded ticking outside border. Type III. All-wire spring unit. Knotted coil construction. Extra firm. This product is a FPI/UNICOR priority item. Federal customers may purchase this product after obtaining a waiver from FPI/UNICOR. Please refer to the FPI/UNICOR Waiver Request Procedures at http://www.unicor.gov 53in. ÌÎÌãåäÌÝÌÒ 75in.