Assemblies or units, specially designed for machine tools, or dimensional inspection or measuring systems and equipment, as follows: (a) Linear position feedback units having an overall ‘accuracy’ less (better) than (800 + (600 × L/1 000 )) nm (L equals the effective length in mm); (b) Rotary position feedback units having an ‘accuracy’ less (better) than 0,00025 °; or (c) ‘Compound rotary tables’ and ‘tilting spindles’, for use with machine tools to or above the levels specified by this category.