100% Cast-Iron Cylinders, Cylinder Heads Connecting Rods, And High Pressure Pistons – More Cast-Iron For Longer Service Life. Two-stage cast-iron pump is significantly more durable than pumps with aluminum components Deep-finned cast-iron cylinders and heads for cool operation Industry-leading cast-iron cylinders high-pressure pistons for extreme durability Ductile iron crankshaft is stronger, more corrosion-resistant and less likely to break