General, TT2021EBF Pump 2.1GPM 1500PSI Turn between 2000 and 3400 RPM. 3400 rpm needed for 2.1 gpm. TT Series 51 Triplex Plunger Pumps - TT2021EBF Pump 2.1GPM 1500PSI - Hollow Shaft, Nema 56-C flanged for direct couple to electric motors - General Pump