Grundfos'' S-tube channel impeller offers high hydraulic efficiency without compromising free passage. While the nature of wastewater presents difficulties with sealing, vibrations, abrasive wear and clogging, the S-tube impeller meets and surpasses all these challenges. Its design eliminates edges, dead zones and cutting functions that wear over time, relying instead on a patented labyrinth and sealing system that provides years of trouble-free operation. The impeller''s simple tube shape eliminates the need for advanced and costly add-on assemblies that are designed to cut, shred or treat the wastewater as it flows from the pump. Meanwhile, a unique new balancing method results in less vibration and noise. Smooth, quiet operation is indicative of greater reliability and a longer lifespan for bearings, shaft seals and other components. The S-tube''s innovative hydraulic design ensures less abrasive wear, enhances anti-clogging capabilities and reduces costs over time.