One quarter in an4 fitting with part number 2021-2-4s
NSN 5975-01-577-4872
NSN 5895-01-264-5186
NSN 6220-00-814-1598
NSN 6320-01-600-0787
NSN 5996-00-156-5010
NSN 5930-00-840-5804
NSN 6110-01-608-0899
NSN 5950-00-269-4805
NSN 7035-00-193-2269
NSN 6130-01-549-4428
NSN 6320-01-145-9013
NSN 6105-00-753-7458