RM Series Pumps - This plunger pump will pump up to 2.5 GPM at 2500 PSI. It spins at 3400 RPM in a direct drive system coupled with a gasoline engine. The matching flange provides convenient connection to most 3/4” and 7/8" shaft 1.1 - 5.5 HP engines. The hollow shafted pump includes a built-in pressure control valve, and chemical injection system. Flows: 2 to 2.5 GPM Pressure to: 2500 PSI Speeds: 3400 rpm Shaft Styles: Hollow Shaft 3/4" and 7/8"