For many people who have two SIM cards, iPhone 4 isn’t the best choice. But the dual SIM adapter iPhone 4 case may change their mind.
Apparently It’s just a common transparent iPhone 4 case, but it comes with a special adapter that allows you to plug your both SIM cards. The dual SIM adapter connects with iPhone 4. Anytime you want, you can switch the active SIM between two cards. All you need to do is select your desire SIM card through SIM Applications in iPhone 4 settings.
The dual SIM card adapter iPhone 4 case is priced at $28.99 USD. If you want one for your two SIM cards, jump to USBfever for more details. Note that the case doesn’t support dual-standby mode.