The ATP B4J Clockwise, Rope Seal pump is a high pressure, keyed, 5 x 4 Flanged water pump with a 13.5 Impeller. When operating at 2,500 RPM this pump is capable of 1,150 GPM at 208 PSI and is primarily use on Off Road , larger mine tank equipment. This ATP Water Pump is a direct replacement for a Berkeley B4 Pump.