Stainless brake line union, 3/16" line, 3/8-24 thread, inverted flare. 1/4 brake line, 7/16-24 Inverted Flare Line Fittings & brass Unions, 12 pcs. 1/4" tube Brass Unions, 7/16-24 Inverted Flare. Stainless Steel 1/4" Brake line unions, 7/16-24 thread, inverted flare (2 pc).