Magnetic drive pumps circulate process fluid to lubricate and cool the bearings supporting the inner rotor. These pumps are used for handling highly toxic liquids. The magnets are attached to the pump shaft and the motor shaft with a nonmagnetic shield between them. It uses permanent magnets to drive the internal motor rotor. The magnetic field set up between the two sets of magnets locks the position of the driven and driving units. When the driving magnets start to rotate, the driven magnets try to keep up, causing the pumping element to rotate. It is used to transfer chemicals and other corrosive materials. Although many of these pumps are of the centrifugal style, many are positive displacement styles. Flow capacities and discharge pressures vary with the type of liquid pumping head that is used.