Magneto-Rheological (MR) grease has been applied to a controllable clutch system. and its performance was investigated experimentally. MR fluid is known as a functional fluid whose yield shear stress can be controlled reversibly by the applied magnetic field strength. But its peculiar characteristics may change as time passes because of sedimentation of dispersed iron particles. https://www.roneverhart.com/Nike-Dunk-Low-Polar-Blue/