Eliminate threaded joints, as well as the labor and parts normally required to make a connection. These 4" union combos can save two inches on road clearance. The fitting's solid design extends its life against corrosive materials, such as acid, which can begin corroding similar fittings at the weld. Fitting are completely interchangeable with all Fig 200/206 unions and save several pounds in weight. This combo is also available in a 5" flange with a 4" Fig 200/206 female sub combination. Special bolt circles available upon request.