Using Apple's world Travel Kit, do I need a devise that transforms 220 volts to 120 volts?

Hey Babis Babinis,

Thanks for the question. Nope! As long as you are using the power adapter that accompanied your MacBook when purchased, you are good to go. Apple’s power adapters support line voltages from 100 to 240 V. In example, see page 3 of the manual for our latest line of MacBooks:

http://manuals.info.apple.com/MANUALS/1000/MA1665/en_US/macbook_pro-retina-late- 2013_ipig.pdf

Additionally, this resource you came from provides some helpful information:

Because the devices listed above have auto-sensing and auto-switching power supplies, all you need to do is attach the correct AC plug adapter to the device to have it work correctly in other supported countries.

About Apple World Travel Adapter Kit

http://support.apple.com/kb/HT4341

Thanks,

Matt M.