This is the replacement Heat Sink Head for the O.S. / 91 SZ-H Ring - OSMG1983. / / FEATURES: Aluminum construction, blue in color / Replaces worn or damaged cylinder heads / / INCLUDES: One heat sink head / One heat sink head gasket / / REQUIRES: Installation / / SPECS: Height: 1.10" (28mm) / Diameter: 2.20" (56mm) / kpm01/31/2006 / ir/jxs