A powerful dual voltage hair dryer is the T3, which can be purchased at Sephora. Its downside is that it is very expensive. I have the full size 110 T3.
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As far as converters...we have a huge, professional one that we used for our 220 Saeco Espresso Machine. The fluctuations of the converter (I think its the hertz) blew out my programmable board. We brought the machine to two different Saeco authorized repair shops and were told that appliances that are used frequently will have a diminished lifespan when used with a converter.