A prosthesis comprising an elastomeric locking liner sized and configured to surround a limb of a patient about a knee joint, the liner having an inner surface for facing the limb of the patient and an outer surface defining an anterior region and a posterior region which are demarcated by an imaginary plane extending midway between the front most portion and rear most portion of the limb along the length of the limb, wherein the anterior region has an anterior material secured thereto and the posterior region has a posterior material secured thereto and the anterior and posterior materials having equal transverse elongation, and the anterior material having a longitudinal elongation greater than the longitudinal elongation of said posterior material, whereby when said prosthesis is donned onto a limb of a patient over the knee and the limb is flexed about the knee, buckling of the prosthesis about the knee is substantially reduced or eliminated and wherein the distal end of the liner includes an insert member adapted to receive a connector for locking the liner to a prosthetic socket when worn on a residual limb of an amputee.