Chrome plated. Die-cast aluminum. Fits S&S 4-1/8" bore SSW+ (Super SideWinder+) V-series engines and 07-17 OEM Twin Cam air and Twin-Cooled engines. Covers can be installed with engine in frame with stock height engines. Clearanced to permit valve lifts up to .640" using S&S valve spring packages and stock rocker arms or S&S roller rocker arms. S&S rocker cover kits come complete with gasket set. Note: See 512384 for replacement S&S rocker cover gasket set. Note: If using valve spring packages with taller than stock installed height; some minor clearancing may be required. Note: In most instances; only minor clearancing is required to use S&S rocker covers with valve springs larger than 1.660" O.D.