Precision Associate’s 8-Rings™ are used almost exclusively as piston seals in pneumatic applications requiring a low profile and long wear. Unlike O-Rings, 8-Rings will not roll or twist. 8-Seal’s unique bumpers reduce premature failure due to nibbling, while preventing pressure trap. For extra long life and lower breakaway pressures, we recommend 8-Rings™ made in our compound 55857. In addition to being internally lubricated, 55857 will perform well at higher pressures and temperatures than standard Nitrile compounds. Compound 55857 is your best choice for dry air applications. PAI 8-Rings are also available in 70 durometer Nitrile (NBR) and Fluoroelastomer (FKM) as well as most of our other 900+ compounds.