The airless spray guns have four parts, the first being the pump, which comes in two different designs but serve the same purpose. One can get a diaphragm or a piston pump. The second is the high pressure hose which is designed to stand the pressure produced by the pump when spraying. Thirdly, there is the grip design available in two to four different models. Finally, there is the tip which controls the flow of paint on the surface. It comes in different sizes for the desired efficiency. All these parts, including the compressor, are assembled in one unit.
The back and forth vibration of the piston, driven by an electric armature, pushes the paint directly out of the gun. This requires some amount of pressure and there is a knob that you can adjust to alter the length of the piston stroke and thus control the amount of paint released from the nozzle. However, it is difficult to obtain a fine line of paint because there has to be enough pressure for the spray work.