① can be used at rest or under various motion conditions; ② Use one alone. Shaped ring, that can seal two-way medium pressure; (3) Any part of the O-ring section can be used as a sealing face, that is, a seal can be formed on the outer diameter, inner diameter, end face or any surface; (4) The motion friction resistance is small, but the starting friction resistance is large; (5) In addition to the wear on the working surface, extrusion failure will occur at high pressure; 6 Simple structure, compact size, convenient assembly and disassembly, and not high technical requirements for filling; ⑦ Wide range of applicable parameters for O-ring sealing. The pressure (static conditions) is 100MPa or higher, and the pressure (moving conditions) is 35MPa. Temperature about -60 ~ 200°C. Axle diameter up to 3000mm. Speed of 2 ~ 3m/s(rotating motion)