Elbow 1/4in M Dob Cone
KOBALT Direct Drive Portable Parts

Price: $20.40
Found under the following brands:
Annovi Reverberi-AR, Westward, Bostitch, Black & Decker, Craftsman, Devilbiss Air Power, DeWalt, Emglo, Excell, Porter Cable, Speedaire
Order nut also if needed