SCS, INC. DK117: Double acting 3-PC piston crown seal combined with L-shaped anti-extrusion / guide rings, Excellent for space saving in compact designs. Outstanding for extremely high pressure and the most vigorous applications, e.g. Construction. Very popular cylinder repair shops, Excellent seal replacement for cylinder tubes that have been honed due to scoring and damage. Integrated anti-extrusion guiding / back-up rings provide extrusion resistance and proper guidance. Very little piston modification is needed when reusing old seal grooves. The snap in design allows for easy installation and is an excellent choice for large piston diameters. Extremely adaptive possibilities for diverse temperatures and media with a wide selection of seal materials. DK117 can be customized to operate in all applications to work with pressure, speed, temperature and fluid compatibility requirements. Available in standard, metric and custom sizes from 0-200″ in diameter.