Wacker Neuson has manufactured and sold these machines for over 40 years in Australia. The spirals help protect the shaft from kinking when put under stress. Adjustable centre spiral allows the operator to place the spiral on tight angles, such as trench edges. This helps straighten the shaft to help protect the inner core. The outer core is made from spiralled steel and covered in rubber. The inner core has core ends that are crimped onto the shaft, not soldered. The 4 vane cast iron impeller is shimmable, this helps keep the pump at optimum performance. The 4 vanes helps reduce load on the shaft and motor and allows for greater pump head. The pump impeller shaft is easily replaced if required. Double bearings and 4 seals ensure long life.