If you’re a frequent traveller, or have a SIM with a great tariff on it, you might well be aware of the many dual-SIM adaptors available for phones. However, USB Fever has upped the ante with the release of a triple SIM adaptor for the iPhone 4 (or 4G as it chooses to call it).
The TRI-SIM will let you switch between three phone numbers, without having juggle several handsets. You don’t even have to cut your SIM card to fit the microSIM slot– you place the adaptor in the iPhone’s SIM slot and the full size SIM sit in the adaptor case. This is available in either black or clear, so you can go for the discreet look or geek out with your SIMs on show.
One downside though is that it would preclude the use of any other protective case you might have – though as it covers the sides – it should solve the infamous antenna issue.
Just to be clear, you can’t use different numbers at the same time – you have to manually switch between SIMs in the iPhone's settings menu, and USB Fever warns that it will take a couple of minutes to recognise the new SIM each time. It’s also not possible to guarantee compatibility with all SIMs, so it’s worth checking first.
While other manufacturers offer handsets with dual SIM slots, one can't imagine the iPhone ever receiving such a feature, so this could be a very useful device, even if only for use on occasions.
The TRI-SIM currently works on iPhone 4 firmwares, 4.0, 4.01, and 4.02, so if you acquire one take care not to upgrade to the forthcoming iPhone firmware updates until you can be sure of compatibility.
Link: USB Fever iPhone 4 TRI-SIM.