Plastic CARB hat is 2-3/8" tall and fits over the 7-1/4" air cleaner opening of Holley Dominator carburetors to prevent water or debris from entering the engine. Solid cover may be drilled when an air cleaner stud is used. The key to success in a car building project is access to high quality, reasonably priced parts that get the job done right. Each Allstar part is the result of our dedication to research and development. Once a need is established, parts are designed and manufactured by talented craftsmen, many of whom are racers and hot rodders themselves. Many Allstar Performance parts are one-of-a-kind; you won't find them anywhere else