Sealed Joint (SJ) chains are designed to protect the pin and bushing from harsh chemicals, dry erosion and overall corrosion. Webster’s sealed joint design is comprised of a resilient Quad Seal housed in a hardened steel ring pressed over both ends of the bushings. This seal, positioned between the inner and outer sidebars, acts as a barrier to keep conveyed material and foreign particles out of the pin/bushing interface, in addition to helping retain the factory installed grease between the pins and bushings to enhance chain performance and wear life.