I have been using them for more than 10 years and have had zero problems as a result. They cut out at either 90v or 135v. The smaller ones I use are rated for 1440w or 12A at 120v. The smaller ones, 3 years ago when I bought 2 additional ones, were about 375 pesos at Best in Guad. I use them for my washer/dryer, refrigerator, pumps, all my TVs individually and all other electronic equipment.