Size:AN6 to AN6. Size: The thread size of 6AN and AN6 ORB is 9/16-18 UNF. 2PCS 6AN Flare to 6AN ORB O-ring Male Fuel Rail Adapter Fitting Aluminum Black. Seal: The AN side of the flare is sealed by a 37 degree angle and The ORB side is sealed with an O-ring.