The Suttner ST-500 spray gun is a low psi gun that is perfect for lower pressure applications,  Has 1/2" inlet and outlet ports, an 8 GPM flow rate, and a maximum pressure rating of 362 PSI.
 
362 PSI maximum pressure rating
8 GPM maximum flow rate
122° Fahrenheit maximum temperature
1/2" FNPT inlet
1/2" FNPT outlet