Stabilizer is the Automatic Voltage regulator. It regulates the output power. It produces the output 230 V ± 1% (Variable 5%) OR 415 ± 1% (Variable 5%) OR As per customer demand for your appliance .

Voltage stabilizers are an effective solution to voltage fluctuation problems. They are designed to current a wide range of Input Fluctuations to maintain specified output voltage. The output voltage waveform is completely distortion free and the regulation is unaffected by the load power factor.

Voltage stabilizer should have the high voltage protection. If the Input is going beyond the limit and Output is going beyond the limit in worst cases The stabilizer should sense Input and Output condition and cutoff the output supply of the stabilizer. So In this way stabilizer protects the connected appliances.

Before selection the stabilizer you need to know how much power you use. By taking an inventory of all the essential electrical loads and doing a basic electrical load evaluation, you can get a good idea how much power your system needs to produce.
Second, you have to know about the power Fluctuations situations also that mean what voltage minimum / maximum you are getting from the main A.C supply. In brief, you have to select the Input Voltage window and the power consumption of your appliance.