You will find on our site air fittings or air hoses equipped with screw fittings that can be of 4 different sizes.
The table below will help you make your choice based on the equipment you own.

Anglo-Saxon name: French name: Outer diameter of the male fitting: Inner diameter of the female fitting: Meets on the following hardware:
1/8'' 5/10 about 9.5 mm about 8.5 mm airbrushes:
Harder & Steenbeck
Iwata
Sogolee
Mecafer
and almost all airbrushes of Asian origin

Compressors:
Generally, all small dry compressors are equipped with a 1/8" outlet
1/4'' 8/13 about 12.7 mm about 11.5 mm - is never found on airbrushes even (too big).
- is usually found on paint guns.
- is most often found on oil bath compressors and compressors sold in large DIY stores.
- the compressor side fittings of the textile sheathed pipes PAASCHE and Badger are in dimension 1/4''
Badger ---- about 5.3 mm about 4.7 mm airbrushes Badger and Thayer & Chandler
PAASCHE ---- about 6.2 mm about 5.8 mm airbrushes PAASCHE