Iwata Air Cap (G3) I6004Iwata Air Cap (G3) I6004 An airbrush is only a true Iwata when it contains genuine Iwata parts. To keep your airbrush operating at peak performance, make sure the model number on the side of your airbrush is listed below. FOR USE WITH: G Series: HP G3 G5 Our parts are precision crafted on the industrys most sophisticated machinery using the finest materials for consistent quality and performance. Every batch, every time.