Manley valve spring cups and locators protect your expensive aluminum heads from being galled by your high-pressure valve springs. They are quality-machined to a .062 in. or .035 in. thickness from heat-treated steel with a corrosion-resistant black oxide finish. Manley valve spring cups and locators are available in inside diameter (spring locator) or outside diameter (spring cup) styles. Image is a representation. Actual product may vary