Dual Double SIM Card Chip Holder Adapter + Case For iPhone 5 4S 4 Description: This Dual SIM case foriPhone5/4S/4 simply makes life very simple , you can happily use The adapter provides a way to switch between SIM cards without switching the iPhone5/4S/4 off which is handy for times when you want to use more data for example, or switch to a SIM card that has more text messages available. Let's say you have a unlocked iPhone5/4S/4 and posses more than one network simcard and wish to swap the network simcards around from diffrent providers be it any reason you like. Currently by phyically switching network simcards manually can get complicated and become time cumsuming and can cause damage to the iPhone5/4S/4 sim gate and internal click in mechanism. How to set-up your DUAL SIM adaptor - Home ==&gt; settings ==&gt; Phone ==&gt; SIM Applications: select your desire SIM card (If you don't want it to select SIM card for you when the signal is low, please don't select "auto/SW) Note once you've chosen to another sim card, it will have a message "No SIM Card installed", please wait 1 or 2 minutes, it needs aound 1 ~ 2 minutes to search, during this time, "No SIM" will appear in the top right of your iphone's screen. Support UMTS/3G Cards and 3G Networks STK Menu:A very simple Powerful STK menu to select default number for making calls, use any of the 2 numbers to make call at any time and divert the primary number to receive calls on both numbers. Check out the following website which might do some help. Youtube Video:http://www.youtube.com/watch?v=Dd9aqyW0_Vo Product particular introduction: Keep Call records function. Support GSM and 3G-USIM card. Special double modes function. Display the on line number in screen. Maintain Original SIM card STK menu function. Two number auto switch on line, easily set the on line time. Two numbers in one phone(Most practical function design). Two number auto switch on line, easily set the on line time. iPhone 5/4S/4(Firmware All Versions ) This is an UPDATED Firmware that SUPPORTS iPhone5/4S/4 without Rebooting( Please if your network SIM card is old version then for iPhone5/4S/4 you might to do air-Plane Mode when you switch) Package Included: 1 x Dual SIM Card Adapter 1 x Back Case for iPhone 5(Green) 1 x R-SIM Nano SIM Card Adapter