I have two adapters that convert the US plug to EU plug. Using one with my macbook pro and the other with my iPhone. both support dual voltage of 220v so i'm not worried. but for the adapter i plug my iphone ac adapter in, i also plugged in my philips g370 buzzer razor which looks like it only supports 110v. i wouldnt be surprised if the philips burns out, but i've also used it with my iphone. at worst, the philips appliance will break and the adapter will keep working right (not damaging my iPhone using through ac adapter) right? Thanks. haven't noticed anything weird yet.