These Rubber Impeller pumps are made of high quality bronze of maximum corrosion resistance. All shafts consist of stainless steel grade 303. Top of the line models have ball bearings and mechanical seals while others have bronze or carbon bearings and lip type seals. Impellers are made of Neoprene Rubber. Nitrile impellers are available as an option. Flexible blades on the periphery of the impeller provide the pumping action. While the impeller rotates the liquid between the blades is continuously squeezed out into the discharge port by a machined in cam located inside the pump chamber.