The purpose of the needle is to control the paint flow. Any damage to your needle can cause very bad paint spray patterns. It is important to keep your needle from getting bend and either straightening the needle or replacing the needle. The air cap and head assembly are on the front of your airbrush and they cover the tip of the needle. When choosing an airbrush compressor keep in mind that put airbrush art onto t-shirts does require a high psi. The psi setting should be between 40 to 60. Make sure that your compressor is rated for the type of work you are going to be doing. In this case it will be airbrushing t-shirts. When doing airbrush art onto t-shirts as a business then invest in a commercial air compressor. Also added with this airbrush art tattoo kit is 1 120gm holographic glitter pack and 100 Vynalaser stencils that are reusable. The kit runs around $544 where as individually purchased these items would cost you around $639. For those of you who have experience in airbrush art tattoos and want a kit that will allow you to open up your own business doing airbrush art tattoos professionally, Airbrush Bodyart has you covered. These tattoos can be applied to any part of the body and last longer than most temporary tattoos. An airbrushed tattoo will last for 7 days unlike other temporary tattoo that start to come off when you are bathing. It takes time or baby oil to remove an airbrushed tattoo. Tattoos that are done with airbrush art look realistic compared to other temporary tattoos. A great cheap plastic to use for stencils is thin plastic folders. These can be picked up cheaply in office supply areas of most stores. When doing airbrush art there are different types of airbrushes that are available. The best airbrush to use for putting airbrush art onto an automobile is a gravity fed airbrush. In the 1940 Walt Disney would show the world a new use for airbrush art. Walt Disney would take airbrush art to the animated screen. The backgrounds for Walt Disney's animated movies were created using airbrushing. Airbrushing allowed them to create shadows and lighting tricks to achieve a more realistic looking background.