A paint spray gun comprises a spray gun body; an air cap; and a hollow needle capable of assuming at least an open position enabling the passage of paint therethrough and a closed position; at least one air distribution channel for atomizing air; and at least one air distribution channel for fan air. A fluid spray single two stage nozzle includes first and second internal surfaces at first and second predetermined angles, respectively, with respect to a rotational axis of symmetry of the nozzle, wherein the first angled surface is proximate a forward opening of the nozzle, the second angled surface is aft of the first angled surface, the first angle is in a range of substantially 0.05 to thirty degrees, and the second angle ranges from substantially 0.1 to sixty degrees greater than that of the first angle.