5H7704 O-Ring Seal Replacement (2) Fits Caterpillar 5H-7704 Fits CAT C15 Turbo ETwo (2) New Aftermarket Replacement O Ring Seals Fits Caterpillar (Fits CAT) Engines and Equipment This listing includes two (2) aftermarket replacement O ring seals Fits Caterpillar (Fits CAT) engines and heavy equipment. The 5H7704 O ring is used at the turbocharger intake elbow connection on C15 and 3406 series engines, providing a static seal to prevent air and fluid leakage. It is a silicone construction seal suited to the high temperature