Proline Fixed Arc Nozzles feature a straight flow valve with a patented open flow design that is engineered for unmatched efficiency and reliability. Unlike traditional valves that force water through restrictive 90 degree turns, this innovative open flow design eliminates sharp angles entirely, allowing water to move smoothly and consistently through the nozzle. This allows for flow rates as far low as 1 GPH. The diaphragm inside does not cause hammering when closing like a typical valve. The operating pressure range is 10-40 PSI with a recommended working pressure of 30 PSI.