The trigger will control the air and the amount of paint that comes out is determined by the needle adjustment on the back of the airbrush handle. Dual action is when the trigger on the airbrush controls both the air and paint. The trigger is pressed down for the air and back for the paint. Now when it comes to the feed on the airbrush there are three types of feeds that you can choose from. Videos can help you learn this advanced airbrush art techniques. You can also get videos that will help you learn how to render a specific design that will fit with the airbrush art you are trying to create. One such specific design video is Creating Killer Dragons, produced by AirBrush Action Magazine with master airbrush artist Crossed Eyed. Or you can scale it down and just airbrush a border at the tops of the walls. Airbrushed borders look more decorative than glued on paper borders on your walls. Thus the interior of your home can be your canvas for your airbrush art. Whether you want bold or subtle the choice is yours when you airbrush. Do not use any knock offs a these will cost you more money and lots of headaches in the long run. You get what you pay for and when it comes to airbrush art you need to go with names that you can trust. A lot of knock offs also will give for a harder time finding replacement parts when they tear up. Knock offs will tear up quicker than the name brands. With needles most artist find that the airbrushes coming out of China bend easier than any of the other airbrushes. So look for one that is made elsewhere so that you do not have to keep trying to straighten a bend airbrush. The best airbrushes to use that are the easiest to take care of are name brand airbrushes. Being able to do micro airbrushing will allow for the artist to create a more realistic and more in depth detail on all small areas of their airbrush design. It is in these small areas that a lot of artist miss the chance to really define the details because they are unable to fully create the detailed area.