End class is

Complex equipment, measuring and responsible medical devices are devices of high sensitivity to power quality. To protect such consumers, it is customary to use stabilizers of increased accuracy with the output voltage range within no more than 3% of the face value. The same accuracy of stabilization is required by lighting devices based on incandescent lamps, otherwise when switching the stages of regulation, lamp light changes noticeable by the eye are possible. The expensive audio — and video equipment of the Hi -End class is perhaps the most demanding electricity consumer. The accuracy of stabilization for nutrition of such loads should be no more than 2% of the face value.