Double nipple/Reducing piece
| (air side) Double nipple Brass G 3/8 outer thread Brass G 1/2 outer thread Reducing piece Brass G 3/8 inner thread x 1/4 NPT outer thread Brass G 3/4 inner thread x 3/4 NPT outer thread Brass G 3/8 outer thread x G 3/4 outer thread |