SCS, INC. DST113: Triangular piston back-up ring for all hydraulic and pneumatic applications. Fits in special shaped housings and in special high pressure or low friction seal profiles. Outstanding seal protection in extreme pressure seal applications, increasing pressure resistance with active control of the extrusion gap. Integrated heal design can be added to most existing piston seal profiles for automatic activation pressure and control. Suitable for large extrusion gaps and large diameter bores. Excellent active pressure control in heavy duty mobile hydraulics applications. Extremely adaptive possibilities for diverse temperatures and media with a wide selection of seal materials. Available in standard, metric and custom sizes from 0-200" in diameter.