This steel brake adapter has a female 3/8-24 inverted flare (convex) port on one end and a 4AN male (7/16-20, 37° convex) on the other end. This part has a large enough hex (5/8") to be used with a crush washer (sold separately) when sealing either the 3/8" side or the 4AN side against a flat faced port. This adapter also has a groove to accept our Retaining Clip (Part No. 3607-001, sold separately) when used as a bulkhead fitting. Sold individually.