Coi Rubber Products, Inc. is a U.S.-based rubber manufacturing and distribution company headquartered in Diamond Bar, California, with operations and production capabilities extending into Asia, including China. Founded on a vision of engineering precision and service excellence, the company specializes in custom rubber molding, extrusion, and sealing solutions for the automotive, industrial, and OEM sectors. With over a decade of steady growth, Coi Rubber has evolved from a niche importer into a vertically integrated manufacturer offering full-spectrum rubber product design, prototyping, tooling, and mass production. The company’s strengths lie in its ability to combine domestic engineering expertise with global manufacturing efficiency, enabling competitive pricing without compromising quality or lead time. Coi Rubber’s product range includes: Automotive rubber components (gaskets, seals, mounts, bushings) Custom extrusions for doors, windows, and weatherproofing applications.