These billet hats are used to make typical short ls3/ls7 style injectors the same height as a conventional ev1 style injector (60mm). These are very commonly used on our Bosch 210 injectors to get the height up for intake/fuel rails that need the tall heigh. They are anodized for great durability against alcohol based fuels. They come with internal pre filters which can easily be removed in the case you dont want to run them. These are for 14mm o ring injectors and the top o ring that comes on these is 14mm also.