Pump plug for use in well operations

Pump plug for use in well operations, the plug comprising a tubular sleeve with a throughbore having a central axis, a plurality of annular sealing fins of resilient material mounted outwardly on the sleeve, each sealing fin being flexible in both directions of the central axis of the sleeve and having at least the central portion thereof symmetrically arranged with respect to a plane perpendicular to the said central axis, and support means mounted on the sleeve on both sides of the sealing fins for supporting the sealing fins in both of the flexed positions thereof, each of said support means being circular in shape and having a diameter less than the adjacent sealing fin, the outer edge of each support means being curved upwardly and inwardly, when viewed in axial cross-section, at least on the surface adjacent a sealing fin, said support means having a thickness sufficient such that the curved outer edge thereof forms a support for that portion of the sealing fin extending radially outwardly beyond the curved outer edge of the support means.