Applications: 1st stage: 28 GPM; 2nd stage: 7.6 GPM. Cast iron body handles demanding jobs. Durable hardened steel gears. Needle bearing construction. Max Pressure 4000psi intermitant, 3000PSI continuous. Max RPM: 4000 Shaft size: 5/8" Keyway: 3/16" Inlet 1" npt Outlet 3/4 not SAE Mount NOTE: Requires about 15 hp or more to run efficiently. Looking at shaft side, pump rotates clockwise - Your engine must spin counter clockwise when looking at the shaft!!!! Pump can be mounted in vertical or horizontal positions - must have 100% positive fluid supply or pump will burn up.