Design highlights include single-inlet, enclosed impellers (mounted back-to-back) and an interconnecting passage between stages. Bronze or bronze-bushed interstage pieces guard against wear. Sizes range from 3-in. to 6-in. (7.6-cm to 15.2-cm) discharge for capacities to 1,000 gpm (3,785 litres/min) and heads to 1,150 ft (351 m).