Back-Up rings refer to rigid rings often used together with lip seals and O-rings to hold plastic or elastomeric seal connections to the designed shape and correct place. They are also used as reciprocal seals for shafts and as seals for pipe connections with different kinds of materials featuring a rigid pipe and a flexible pipe. Back-up rings that are used as direct reinforcements of stiffer material for preventing leakages in pneumatic cylinder piston sealing, in cases where a softer flexible seal risks being pulled out or torn from its seat. They are also used to hold elastomers in place during machine assembly, especially when it is impossible to check the seal post-assembly. Rubber-contoured back-up rings are commonly manufactured in 90 durometer nitrile to provide adequate stretching and snap-back elasticity. In pipe connections, they used to hold the connection between polyethylene pipes like HDPE pipes and steel fittings, or steel pipes. The back-up ring gets placed on the HDPE flange adapter and matches the specifications of the steel pipe or fitting. Let MRO Supply be your single source convenience for all industrial products including supplies, tools and equipment. We strive to the leading supplier of high quality tools, supplies and equipment to offer our customers lasting solutions sourced from the best manufacturers in the industrial arena. Talk to us today to keep your manufacturing plant up and running.