You'll want to get a dual voltage strip. Even if you get a strip that isn't sold as having surge protection a plain old power strip will not work with 220 volts, unless you want a big pop and a burning smell when you plug it into 220 volts. Also remember that dual voltage strips are not transformers, if it's plugged into 220 the power in the outlets will be 220, but nowadays most chargers for phones, laptops, etc are all dual voltage. There are plenty of cheap, dual voltage power strips that are small enough to be easily packed.