This document discusses magnetic responsive (MR) fluids, which are fluids whose viscosity and yield stress can be precisely controlled by an applied magnetic field. MR fluids have particles that are polarized and form chains when exposed to a magnetic field, limiting their movement and the movement of the fluid. The document describes three modes of MR fluid flow - valve, shear, and squeeze - and discusses applications in damping, brakes, and valves where the fluid's dynamic properties can be controlled with high precision by the magnetic field.