Abstract: A plug is disclosed for sealing off in a tubing having a sealing surface. A housing contains an annular metal seal means and two sets of segmented expanding lockdown rings that react with three solid rings to provide a downward motion. The expanding lockdown rings consist of a solid tapered ring that has been cut into a number of arcs. When a tapered mandrel is forced down inside the arcs, the arcs are expanded to the outside diameter of the mandrel. As the arcs expand, they are wedged between the solid rings that have matching tapers. The solid rings react between locking dogs and a shoulder in the housing to provide the downward movement. By using several expanding lockdown rings and solid rings, a relatively great deal of vertical motion can be obtained through the combined wedging action of each ring. Means on the housing and the tubing may be used to limit the locking load on the annular seal means.