The cement retainer is a field-proven, modular, cast-iron, drillable isolation tool for various applications. Changing the top slips enables the versatile retainer to be set mechanically or on a wireline setting tool. Replacing the sleeve valve with a solid plug converts the retainer to a bridge plug. The retainer enables pressure testing before cement squeezing. The surface-controlled valve automatically closes when the stinger is removed to maintain the squeeze pressure while excess cement is circulated out. The valve also isolates hydrostatic pressure to protect sensitive zones. The rotationally locked, cast- iron components enable a fast drillout to save rig time.