This steel brake adapter has a female 10x1.00mm DIN bubble flare (concave) port on one end and a 4AN male (7/16-20, 37° convex) on the other end. This part also has a large enough hex (5/8") to be used with a crush washer (sold separately) when sealing the 4AN side against a flat faced port. Sold individually.
Male vs Female, Convex vs Concave