Header Builder Kit, all 304 Stainless Steel, 1-5/8" dia. x .065 wall primaries. Kit includes (2) 3/8" thick Laser cut flanges (to be specified by customer), (12) J-bends (one 6" long leg and one 12" long leg), (2) 3.000" dia. outlet formed collectors and (2) filler diamonds to connect the tubes together. We recommend the use of 308L SS welding rod.