AR Series Step Up / Step Down Voltage Converter with Regulator (Stabilizer) provides a stable source of power for all major appliances and sensitive electronics. Each model is CE approved and certified. In addition to converting 220/230/240 volts to 110/120 volts and visa versa, these voltage regulator transformers will stabilize either 120 volts or 220 volts. What that means is they will provide stabilized 120 volts when the input is 120v as well as providing a constant stabilized 220 volts when the input is 220/230/240 volts. The input parameters for stabilization (regulation) of power are 80 volts – 140 volts and 120 volts – 240 volts. The output is stabilized to either 110 volts or 220 volts +/- 4%. Heavy-Duty 2 in 1 step up-down voltage converter and Stabilizer/Regulator for continuous use. Converts 220/240 volt to regulated 110 volt. Converts 110 volt to regulated 220/240 volt. Regulates the power flow to protect appliances against damage caused by voltage surges, voltage drops and spikes. Works well with audio and video equipment, computers, electronics, refrigerators, freezers and many other appliances. Safety Cut-Off function allows unit to shuts-off automatically in case of power fluctuation and turns back on in safe power range.