Apple iPhone 4 comes with a MicroSIM option which is going to need the cutting of your normal SIM card into a smaller size. Even if you convert your normal SIM.
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Dual SIM Card Adapter for Apple iPhone 4 | Apple Blog
Dual SIM Card Adapter for Apple iPhone 4 | Apple Blog
Apple iPhone 4 comes with a MicroSIM option which is going to need the cutting of your normal SIM card into a smaller size. Even if you convert your normal SIM.