When you buy mobile phones from your network carrier, it will be usually locked or restricted from using other carrier services. It means that you will not be able to use that handset with SIM cards of other carriers unless you unlock Windows phone. Windows Phone Unlock Advantages: Let us now first look at advantages of unlocking Windows phone. • Firstly, if you are traveling to international destinations, you will not be able to use the local SIM card to avoid the international roaming charges of your phone carrier. • Secondly, unlocked phones will fetch you better resale value, because your buyers will obviously want to use their own SIM cards after purchasing the phone from you. Iphone 4 64gb Unlocked Ebay. Buy Unlocked Nokia Phone. Apple Iphone Unlock Guide on this page.