1.Peel 520 change iPod Touch into iphone cell phone. This is really good news for those who want to buy iphones or want ipod touch with talking functions. What is more important is that. it can save a lot of money. Actually, Apple Peel 520 is a type of communication module back on the module, the SIM card slot, still have batteries and related components. 2.Use a regular sim card to make phone calls with a IPod Touch is now possible with the Yosion's Apple Peel 520. Internally, the case is equipped with a PCB (Printed Circuit board) integrated with Infineon baseband processor that is able to hook up to cellular network to provide 3G voice and data usage. 3.520 is actually a Communication Module that works with a jailbroken iPod Touch. It comes with a SIM card slot and battery built in. Made from soft material with the antenna locate at iPod Touch earphone jack. Powered by an Infineon baseband chip, this adapter not only offers voice calling and text messaging, GPRS not possible yet, but it also doubles up as an 1200mAh battery and provides 4.5 hours of call time or 120 hours of standby juice.