I have an ISB Sola Basic Voltage Corrector 4000 made in Mexico
It is a 30amp model I purchased last winter in Hermosillo. Cost was under $200 U.S. I have a 50Amp system but figured in Mexico pretty much all I see is 15,20,30 amp connections.
The store is an electric outlet and I called and had them have one ready for me when my friend was in town. They normally don't carry stock. They get them from factory which I believe one is Hermosillo.
Unlike the 50amp voltage booster I purchased for $500 years ago this lowers and raises voltage. Big demand in Mexico households because of voltage irregularities.
I can get name of store and phone number if you like. We are picking up another for a friend on way down this winter.