There are internal thread (female adapter) and external thread (male adapter) available, and they both feature 16 mm threads and 1.5 mm pitch.
Spray Gun Cup Adapter, 16mm Thread 1.5mm Pitch Paint System Female Adapter
Car Spray Gun Cup Adapter, 16mm Thread 1.5mm Pitch, MPS Female Adapter PRO-33, P
Car Spray Gun Cup Adapter, 16mm Thread 1.5mm Pitch, PRO-33 PRO-44 PRO-88 HVLP Sp
16mm Thread 1.5mm Pitch MPS Female Adapter, Paint Cup Adapter PRO-33, PRO-44, PR
16mm Thread 1.5mm Pitch MPS Female Adapter PRO-33, PRO-44, PRO-88 HVLP Spray Gun
