Where () is shear stress, K is the consistency constant (equal to the viscosity at a shear rate of () and approximately proportional to Mooney viscosity), () is the shear rate and n is the power-law index. The power-law index is a measure of deviation from simple Newtonian behaviour and is a valuable indicator of behaviour in high rate processes. Values of n for most rubber compounds are in the range 0.1 to 0.3. If two rubber compounds have similar values of K but different values of n, their Mooney viscosities will be similar but their behaviour in extrusion or injection molding will be substantially different. This can be seen by considering the apparent viscosity ():