These flexible impeller pumps have 2 self-contained ball race bearing units. They are more compact than the plain bearing pumps, require very little maintenance (do not require greasing) and can run for longer periods at higher speeds giving greater output and less wear and tear on the pump. The pump body is manufactured from pressure gunmetal bronze with stainless shaft, 2 x ball race bearings units and fl exible neoprene impeller. Sizes referred to are the internal female BSP size of the inlet / outlet ports.