Prince Double Relief Cushion Valves: Prince No. DRV-4HH, 1500-3000 PSI Adj. Range, 1/2&rsquo;&rsquo; NPT Port Size, 2000 PSI Relief, 222804 Prince Double Relief Cushion Valves Port Size: 1/2" NPT PSI: 1500-3000 Relief Setting: 2000 PSI GPM Flow: 30