Rugged Construction: Cast iron construction in close coupled and frame mounted design. Superior Priming: High suction inlet and internal suction check valve keeps more liquid in the casing for faster priming and repriming. Diffuser Priming: The patented diffuser design allows impeller trim, reduces internal wear and eliminates radial loads. High Efficiency: Enclosed, trimable impellers provide efficiencies from 60-75% for low energy costs. Dimensional Interchangeability: Four pump groups allow performance to be changed with replaceable impellers and diffusers.