<p>A method and apparatus for a cement retainer for use in a subterranean well is described. The cement retainer typically includes a mandrel and a packing element. The mandrel may have an outer surface and a. non-circular cross-section and the packing element may be arranged about the mandrel, the packing element having a non-circular inner surface matching the mandrel outer surface such that concentric rotation between the mandrel and the packing element is precluded. The apparatus may include slips having cavities to facilitate removal of the apparatus. The apparatus also may include a valve for controlling upward fluid flow through a hollow mandrel. The valve may include a flapper having at least one tab to engage at least one recession in the mandrel such that rotation between the mandrel and the valve is precluded when the valve is in a closed position. The apparatus may further include a central member which is releaseably attached to the mandrel by a release mechanism.</p>
