The Gaahleri GHAC-98D is a superior airbrush in the Gaahleri range. It is a double-action, gravity-fed airbrush of traditional design, with 0.50mm and 0.38mm needles and improved polishing of needle and cup. 

It is presented in an elegant black rigid cardboard box protected by a sliding cover. 

The exploded view is printed on the inner face of the lid, a convenient way of avoiding loosing it. Inside, the components are protected by a foam sheet.The contents of the box are

• The airbrush 
• 0.50mm nozzle and needle
•  0.38mm nozzle and needle
• lubricant 
• spare o-rings
• 1/4 oz. cup with lid
•  quick connector for air source  

Also included is a booklet with instructions in English.

Externally it is almost identical to the GHAD-39  but the differences are internal, with a superior polished cup and needles, which provides better paint flow and makes cleaning easier.

In the hand the airbrush is solid, not excessively heavy and comfortable to hold. The movement is smooth although the trigger is slightly stiff.

The airbrush features a floating nozzle for ease of cleaning and changing as no tools are required for disassembly. In addition, it has a needle stroke limiter that allows you to set the stop and maintain a constant line width effortlessly. 

The cup is detachable for better access and cleaning.

The seals in contact with the paint are made of Teflon, which is more resistant to solvents than rubber seals. The air connection is a standard 1/8" thread, although a quick connector is included as well.

The air cap is round and fully enclosed, good for backflush cleaning. Here you can see the difference in size for the needles and nozzles included.

In use you can feel that it is a superior range, the paint comes out with less dispersion.

I didn't notice much difference between the two needles, offering a similar line width. For practical purposes, you could almost consider that it comes with a spare needle and nozzle.

In any case the spray is uniform, easily controlled and the paint goes where you expect it to, with no flaws or problems.

Below are some tests of use, varying the pressure on the trigger and the distance to the paper. These should not be considered a sample of the airbrush's capabilities, as I am not an artist, but tests for performance and ergonomics. The tests were made with Vallejo Model Air black, with its thinner.

Lately I have also used it on models several times, performing perfectly and giving no problems during use or cleaning. In fact, the superior polishing on the cup not only makes painting easier, but also makes cleaning faster, as the paint sticks less.

Test with 0.38mm needle

Test with 0.50mm needle

Conclusion

A very complete airbrush, with  absolutely satisfactory performance . It has two similar needles for general use and includes  cup lid, a needle stroke limiter and teflon seals. It also comes with spare o-rings and lubricant as standard. Disassembling and cleaning is specially easy thanks to the floating nozzle and polished cup.