The Udor KAPPA-120/GR Diaphragm Pump uses gear reduction to enable use on 18 Ð 23 horsepower engines with 1" shafts. This pump generates a maximum gallons per minute rate of 35 with a maximum of 700 pounds per square inch and is internally manifolded with anodized aluminum. Large 1-1/2" hose barb inlet allows for maximum flow.