Abstract: A sealing device that includes at least an integral base and sealing lip is provided. The sealing device can operate over thousands of cycles of operation without unacceptable wear and over a substantial range of possible temperatures. The dimensions and/or geometric shapes of the sealing lip contribute to the desired sealing results when the sealing device is part of a piston assembly, a valve assembly, a spool assembly or other appropriate assembly. One or more of the structural features can be included in the sealing device. These features can relate to the height, thickness(es) and angle of the sealing lip.