An apparatus for adjusting and then maintaining the leveling support of an assembly relative to the surface upon which that assembly has been placed. The apparatus can be locked or maintained in place to prevent the loosening of the adjustment if the assembly is moved. The apparatus is comprised of an elastomeric material molded concentrically around a threaded stud to form a foot; a plurality of longitudinal grooves on the interior wall of the foot; a plurality of longitudinal ridges on the outside surface of an extension from the base section of the assembly; and, a threaded insert within the extension that can mate with the threaded stud.