Dual Sim on Iphone3GS

[n121277]

Hello,
Please recommend me the best dual sim adaptor for iPhone3GS. I have already got 2 mobiles and might get one more in the following week (office). Any recommendations welcome
Thanks
NJ

 

[isabellajack]

Has anyone tried this 3-in-1 External Battery with DUAL SIM Function for iPhone?
If so, can you advise if this actually works as stated?iPhone 5 Release Date