Jegs Stainless Steel "Male/Female" V-Band Flanges utilize a interlocking seating surface to ensure a leak-free seal without the need for a gasket and provides an easy way to align the flanges during installation. The butt-weld side of our V-Band Flanges are CNC machined with a counter-bore to allow the matching tube size material to slip into the V-Band Flange and be welded in place with the proper alignment. Flange Dimensions: 3.500 in I.D. with .125 in. recess for tube fitment & overall assembled width of 1.5625 in.