This AN815 flared union fitting (EDMO# AN815-4D) is an aluminum, male to male fitting with a 1/4-inch tube outer diameter and 7/16-20 threads.
AN816-4D is an aluminum straight fitting with a 1/8 inch pipe to 1/4 inch 37 degree flare.
AN806-3D is a fared aluminum tube plug with a 3/16 inch outer diameter and 3/8-24 threads.