This steel adapter has a female DIN M14 (14x1.5mm, 24° convex seat) on one end and a 6AN male (9/16-18, 37° convex seat) on the other.
The two-piece design allows you to hold the adapter while screwing down the female threads. This avoids damage to the sealing surface, but requires the correct European 24° DIN concave seat on the male fitting. It cannot be used with a crush washer on Japanese systems. Sold individually.
Male vs Female, Convex vs Concave