lol I have this baby myself http://www.amazon.co.uk/Goldsource-ST-3000-Voltage-Converter-Appliances/dp/B00EORTLFA/ref=sr_1_2?s=electronics&ie=UTF8&qid=1390502904&sr=1-2&keywords=Converter+3000
I have found those for the Xbox one but I have to check something.... the output seems to differ I know with the 360 slim they had 2 different ones.... maybe it's the same for Xbox one....
http://www.amazon.fr/Bloc-Alimentation-Adaptateur-Secteur-XBOXONE/dp/B00EO4K6MK/ref=sr_1_16?ie=UTF8&qid=1390502109&sr=8-16&keywords=xbox+one+ac
http://www.amazon.fr/Adaptateur-Adapter-Chargeur-dAlimentation-Console/dp/B00HN3K78C/ref=sr_1_5?ie=UTF8&qid=1390503194&sr=8-5&keywords=xbox+one+adaptateur
but it is quite easy to find out.... you take your power brik you will get with your Xbox you check the output rating and you look for one that has the same rating than the original one....
and of course make sure it takes 220v in input for the new one or you can buy a converter like you found and to be safe I'll advise to take twice the wattage you need for the Xbox one or at least 1.5X so at least 300watt converter like these
http://www.amazon.co.uk/Goldsource-ST-300-Watt-Voltage-Converter/dp/B00A4DI7FS/ref=sr_1_5?s=electronics&ie=UTF8&qid=1390503567&sr=1-5&keywords=Converter+300
