Peel Vooma PG92, an artificial casing "Vooma" that can provide additional functionality on the iPhone 4. By using this casing, the iPhone 4 can be converted into a dual SIM card phones.
Function can be performed if it has been to download an application Vooma that serves to do jailbreak the iPhone 4. After the jailbreak is done, then this phone should fully can be used as dual SIM card which many in the market.
The additional SIM card is placed in the tool itself. From TechCrunch notes, this tool works fine.