A ringless high pressure moving seal has been developed which can reach pressures as high as 1200 MPa. A unique feature of the seal is the elastic action of its plunger. This action results in full oil film operation that enhances volumetric efficiency while reducing leakage. Analysis and results of the pressure examination are presented. It is shown that the seal operates with high volumetric efficiency, very low friction and no wear.Presented at the 49th Annual Meeting in Pittsburgh, Pennsylvania May 1-5, 1994